Note: Descriptions are shown in the official language in which they were submitted.
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Title: SYSTEM AND METHOD FOR MAKING BRACES FOR DIES
Field of the invention
[0001] This invention relates to a system and method for producing
braces for a cavity die. The invention may also have application in other
fields
in which a strip material must be cut to fit to a boundary.
Background of the invention
[0002] U.S. Patent No. 6,233,309 describes a cutting knife that can be
detachably connected to a baseboard. The cutting knife extends in a
perpendicular direction to the baseboard and circumscribes the knife cavity on
the baseboard. At least one elongated cross member is affixed to the cutting
knife and extends across the knife cavity. The cross member is mounted to
the baseboard by a removable fastener. The cutting knife may then be
removed from the baseboard and re-secured. The cutting knife described in
the '309 Patent does not provide any means for designing and producing
braces for cutting knives of various shapes. U.S. Patent No. 6,233,309 is
incorporated herein, in its entirety, by this reference to it.
[0003] Accordingly, there is a need for systems and methods for more
easily designing and producing braces for dies.
Summary of the invention
[0004] It is an object of the invention to improve on, or provide a useful
alternative to, the prior art. It is also an object of the invention to
provide
systems or methods for designing or producing braces for dies or designing or
cutting a strip material to fit a boundary. The following summary is intended
to
introduce the reader to the invention by not to define the invention. The
invention may reside in a combination or sub-combination of elements or
steps found in this or other parts of this document, for example in the
claims.
[0005] According to a first aspect of the invention, a system for
producing a brace for a cavity die having a predetermined shape is provided.
The system comprises: a) an input file containing information about the
predetermined shape of the cavity die; b) a data processor configured by a
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bracing program to produce an output file from the input file and a plurality
of
brace parameters, wherein the output file comprises information about the
design of the brace; and c) a brace-making machine adapted to produce the
brace, the brace-making machine adapted for communication with the data
processor; wherein the data processor is adapted to instruct the brace-making
machine to produce the brace from the information in the output file.
[0006] According to a second aspect of the invention, an apparatus for
producing a brace for a cavity die from a strip of material is provided. The
apparatus comprises: a) a bed for supporting the strip of material; b) a
material feeder for moving the strip of material in a first direction; c) a
cutting
tool movable in a second direction across the strip of material; and d) a
control system for coordinating the movement of the material feeder and
cutting tool to make a desired cut in the strip of material.
[0007] According to a third aspect of the invention, a method of
producing a brace for a cavity die having a predetermined shape is provided.
The method comprises: a) providing input information to a data processor,
the input information comprising information about the predetermined shape
of the cavity die and brace parameters; b) processing the input information by
the data processor to produce an output file containing information about the
design of the brace; and c) producing the brace in accordance with the
information from the output file.
[0008] According to a fourth aspect of the invention, a method of
producing an output file containing information for the design of braces for a
cavity die having a predetermined shape is provided. The method comprises:
a) providing input information to a data processor, the input information
comprising information about the predetermined shape of the cavity die and
brace parameters, the brace parameters comprising brace width, starting
brace centre point from edge, minimum brace spacing and maximum brace
spacing; and b) processing the input file and the brace parameters to produce
the output file, wherein the processing step comprises:
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[0009] i) drawing a pair of edge braces having parallel centerlines and
located at the starting brace center point from edge distance from the
furthest
points of the cavity die perpendicular to the centerline of the edge braces,
the
edge braces having a constant width equal to the brace width and end profiles
determined by intersection with the shape of the cavity die; and
(0010] ii) if the distance between the edge braces is greater than the
maximum brace spacing, drawing a number of interior braces having
centerlines parallel to the edge braces and regularly spaced between the
edge braces, the number being the lowest number such that the regular
spacing is between the minimum brace spacing and maximum brace spacing,
the interior braces having a constant width equal to the brace width and end
profiles determined by intersection with the shape of the cavity die.
[0011] According to a fifth aspect of the invention, a computer readable
medium having a computer program recorded thereon for producing an output
file containing information for the design of braces for a cavity die having a
predetermined shape is provided. The computer program causes the
computer to perform the steps of: a) accessing information about the
predetermined shape of the cavity die; b) accessing brace parameters relating
to the location of the braces, the brace parameters comprising brace width,
starting brace centre point from edge, minimum brace spacing and maximum
brace spacing; and c) processing the input file and the brace parameters to
produce the output file, the processing step comprising:
[0012] i) drawing a pair of edge braces having parallel centerlines and
located at the starting brace center point from edge distance from the
furthest
points of the cavity die perpendicular to the centerline of the edge braces,
the
edge braces having a constant width equal to the brace width and end profiles
determined by intersection with the shape of the cavity die; and
[0013] ii) if the distance between the edge braces is greater than the
maximum brace spacing, drawing a number of interior braces having
centerlines parallel to the edge braces and regularly spaced between the
edge braces, the number being the lowest number such that the regular
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spacing is between the minimum brace spacing and maximum brace spacing,
the interior braces having a constant width equal to the brace width and end
profiles determined by intersection with the shape of the cavity die.
Brief description of the drawings
(0014] One or more embodiments of the invention will now be
described, by way of example, with reference to the following figures:
[0015] Figure 1 is an isometric view of a braced cutting die.
[0016] Figures 2A through 2F are plan views of a selection of dies of
various shapes.
[0017] Figure 3 is a schematic representation of a brace making
system.
[0018] Figure 4 is a flow chart of steps followed to determine the shape
and location of braces.
[0019] Figure 5 is a flow chart of the sub-steps within step 48 of Figure
4.
[0020] Figure 6 is a front elevation view of a brace-making machine.
[0021] Figure 7 is a back elevation view of the brace-making machine.
[0022] Figure 8 is a partial plan view of the brace-making machine.
[0023] Figure 9 is a schematic representation of an end clamp of the
brace-making machine.
[0024] Figure 10 is a schematic representation of a piston unit of the
brace-making machine.
[0025] Figure 11 is a schematic representation of a guide mechanism
of the brace-making machine.
[0026] Figures 12, 13, and 14 are schematic representations of a
computer control system for the brace-making machine.
[0027] Figure 15 is a flow chart of method of producing a brace.
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Detailed description of the preferred embodiment
[0028] Figure 1 is an isometric view of a cutting die 10. Cutting die 10
has a knife 12 constructed from a strip of material having a cutting edge 14
on
one of its sides. The knife 12 is bent at various angles to provide a closed
predetermined shape or cavity defined by the point of the cutting edge 14.
The knife 12 is typically made from steel. The cutting edge 14 may have
various types of bevel such that the point of the cutting edge 14 may be in
the
centre of the thickness of the knife 12, offset to one side, or at one edge of
the
knife 12. Depending on the application, the knife 12 may have perforations in
its sides, gates cut out of the cutting-edge 14, or notches cut out of the non-
cutting edge.
[0029] The die 10 also has braces 16 which serve a number of
purposes. Depending on the application, these purposes may include one or
more of: (i) supporting the knife 12 or helping to maintain the shape of the
die; (ii) distributing the forces from the die 10 to a base board (not shown),
(iii)
providing a means for mounting dies to a base board, and (iv) providing a
means for mounting other items, such as cut-outs, punches, stabs or slit
knives, to the die 10.
[0030] Continuing to refer to Figure 1, the braces 16 are typically
located within the area bounded by the knife 12 to avoid interfering with any
adjacent dies mounted to the same base board. The braces 16 are typically
made of steel and welded at their ends to other braces 16 or to the knife 12.
The braces may be cut from a strip of material (also known as "strip stock"),
their ends being cut to match the inner surface of knife 12, or any other
surface to which they are attached, to within the tolerances required by
welding or any other method of attachment used. In the case of a die 10
intended to be mounted flush with the surface of a baseboard, as for the die
10 shown, the braces 16 are mounted flush with non-cutting edge of the knife
12 and include holes 18 for inserting a fastener, such as a screw, to attach
the
die 10 to a baseboard. For other sorts of dies, the braces may be located in
different locations. For example, for dies in which the knives 12 will be
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embedded into a baseboard, the braces 16 may be located at a point
between the two edges of the knife so as to contact or remain above the
baseboard when the knife 12 is pounded into the baseboard. The knife 12
may also have nicks 20, also called marker notches, which are used, for
example, to provide alignment or folding tabs in the material to be cut by the
die 10. The nicks 20 may extend only partially into the knife 12 as shown or
may extend to the non-cutting edge of the knife 12. If the nicks 20 extend
through the plane of the braces 16, the braces 16 may be cut to the contour of
the nicks 20 or the location of the braces 16 may be adjusted to avoid the
nicks 20.
[0031] Figures 2A to 2F show plan views of a selection of dies 10 of
various shapes. As shown in the figures, the braces can have a variety of
configurations and locations. For example, die 10a in Figure 2A includes
braces 16a extending between interior surfaces of the knife 12a. The braces
16a' shown closest to the left or right side of the die 10a may be called edge
braces. The other brace 16a" may be called an interior brace. Braces 16p,
which may be called supports, may be attached, for example by welding,
between the other braces 16. Other braces 16b, which may be called tabs,
may be attached, for example by welding, between the interior surface of the
knife 12a and a brace 16a. Die 10b in Figure 2B includes a set of braces 16c
extending parallel to each other and additional braces 16d and 16e that are
not parallel to braces 16c. Die 10c in Figure 2C includes a set of braces 16f
supporting the knife 12c and an additional brace 16g, which may be called a
cross-brace, supporting a punch 22. Aside from the punch 22, the cross-brace
16g might support other items, such as cutouts, stabs or slit knives, in
position
relative to the knife 12. The punch 22 or other items may be attached to a
brace 16 by various means including welding, fasteners, such as screws or
clips, or a press fit into a hole in the brace 16. Multiple braces 16 may be
used
to support large punches or other items. The cross-braces 16g may be
separate braces provided only to provide a punch or other item or may be
braces 16 provided for other purposes that additionally perform the function
of
a cross-brace 16g.
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[0032] The dies 10 and braces 16 described in Figures 2A-C are typical
of the majority of dies 10. However, dies 10 of unusual shapes occur from
time to time and may be braced to account for their unusual shape. For
example, die 10d in. Figure 2D has a set of braces 16h parallel to one
direction and a second set of braces 16i parallel to another direction. The
two
directions each correspond to the shape of a part of the die 10d. The two
directions are generally perpendicular to each other in the die 10d although
other dies may have directions at other angles to each other. The die 10e of
Figure 2E has a set of braces 16j' spaced at multiples of a constant spacing
interval and a brace 16j" spaced at a different spacing. The location of brace
16j" is adjusted to support the interior corner 22 of the knife 12f but
without
requiring a cut in the side of brace 16j". Brace 16k may also be added to
reinforce the peninsula in die 10e. Die 10f in Figure 2F has braces 16m and
161, which may all be called edge braces, forming a closed shape, such as a
rectangle, inside of the knife 12g. Braces or tabs 16n extend from brace 161
to the knife 12g. Brace 161 also extends to the knife 12g but may optionally
extend only to the outside edge of brace 16m. In that case, tabs may be
added to replace the lost extensions of brace 161 and provide connection with
the knife 12g either in the same location as the lost extensions of braces 161
or in other locations. Additional tabs 16o may be added. The bracing scheme
used in Figure 2F can be generally described as having a set of braces 16
forming a closed shape within the die 10f and having a set of tabs 16n, 160
and the extensions of 161, extending to the knife 12g.
[0033] Dies 10 of shapes other than those shown in Figures 2A through
2F may also occur in practice and braces 16 as described in one or more of
these figures may be selected, combined or adapted to provide bracing.
[0034] Figure 3 shows a system 30 for making braces in accordance
with a preferred embodiment of the present invention. The system includes
any suitable data processor, such as a computer 31 which executes
instructions from a bracing program 32 (described in detail below) loaded
thereon. Input devices, such as a keyboard 34a and drive 34b, or other input
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devices, allow for the input of an input file 3 3, and optionally brace
parameters, to the computer 31. An output file 35 with information, for
example regarding the shape of one or more braces to be cut, may be
communicated from the computer 31, optionally via any suitable
communications network 36, to a brace-making machine 38 (also referred to
as the apparatus) described in detail below. The brace-making machine 38
receives the output file, reads the output file to determine the shape of one
or
more braces 16 to be cut, and cuts the one or more braces 16. Alternately,
the output file from the computer 31 may be output, optionally through the
communications network 36, to a printer or plotter 39. The printer or plotter
39
reads the output file and produces a drawing showing the shape of one or
more braces 16 to be cut. The printer or plotter 39 may also produce a
drawing showing braces 16 in position in a die 10 to be braced to aid in later
assembly of the die 10.
[0035] The operation of the computer 31 running the bracing program
32 will now be described with reference to Figures 1, 3, and particularly
Figure
4.
[0036] The operation begins at step 40, where the input file 33 is
loaded into the bracing program 32. The input file 33 includes information
about the shape of the die 10 to be braced. To load the input file 33, a user
may, for example, browse through and select a file from one or more folders
of available files on drive 34b, or otherwise specify a file to be loaded. The
input file 33 may correspond to an article of manufacture or production run
and may contain information on the shape of a number of different dies.
[0037] The bracing program 32 is adapted to read the input file 33 in
one or more forms and according to one more protocols. For example, the
input file may be a Data Exchange File (DXF) file created in a separate
drafting program, such as AutoCADT"" as supplied by Autodesk Inc., which
contains information about the shape of the die. The die shape is made up of
several line segments, for example segments corresponding with the shape
enclosed by the point of the cutting edge 14.
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[0038] The protocol may include rules for preparing or formatting the
information within the DXF file. For example, the bracing program may
require that all data relating to the shape of a die 10 be tagged with a group
code number distinct from the group code number of any other information in
the file. This allows the bracing program to identify and separate information
relating to the shape of a die 10 to be braced from information relating to
other
dies 10 or title blocks, notes, or other information in a file. In files
prepared in
AutoCADT"", this is achieved by placing the information relating to the shape
of the die in a distinct BLOCK enclosed by BLOCK ... ENDBLK. Multiple dies
can be included in an input file as long as each is included in its own block
and the ENTITIES section is set to display all shapes if required to allow an
operator to choose the die 10 of interest. The protocol also includes rules
regarding the scale and units to be used, for example, that the scale will be
1:1 and all units will be inches. The protocol may also include rules
prohibiting any type of shape description not understood by the bracing
program, which may include, for example, ARC or POLYLINE functions in
AutoCAD. Alternately, the bracing program 32 may be modified to avoid the
need to address some or all of these issues in the protocol. For example, the
bracing program 32 may be modified to read ARC or POLYLINE functions
and convert them to a series of line segments.
[0039] Other rules may also be included in the protocol to aid the
bracing program 32 in performing various functions. For example, rules may
relate to the organization of information about a die 10 within layers of a
block.
For example, the basic shape of the die 10, or the point of its cutting edge
14,
may be included on one layer while information on the location of punches or
other internal features of a die may be placed on separate layers. This allows
the bracing program 32 to locate information required for certain steps and
separate the required information from other information contained in the
complete file for the die 10. Alternately, the bracing program 32 may be
modified to solve or bypass issues addressed in the protocol so that the
protocol may be simplified. For example, the bracing program 32 may be
modified to include routines which scan the input file 33 and identify
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perimeters of dies and features inside the perimeter of a located die such
that
information does not need to be provided in blocks or layers as described
above.
[0040] In step 42, the input file 33 is converted if required. Although
step 42 is shown as part of the bracing program 32, a separate program may
also be used to perform the conversion either before a file is input to the
bracing program 32 or upon receiving a file exported from the bracing
program. Step 42 may also be embodied in one or more routines of the
bracing program 32 which run automatically, optionally without input from a
user or reporting to a user. Further, step 42 may be broken into various
component steps or conversions performed by one or more separate
programs or sub-routines of the bracing program 32 at other suitable locations
within the overall process or at dispersed locations within the overall
process.
[0041] Step 42 may include operations to bring an input file into
compliance with the protocol. For example, step 42 may include moving
information in an input file between blocks so that all information regarding
the
shape of a die 10 is located in a distinct block for each die 10. Un-supported
shape information, such as a POLYLINE, may be converted to a series of line
segments.
[0042] Step 42 may also include operations to facilitate the work of the
bracing program 32 in place of expanding the protocol or requiring other
operations later in the overall process. For example, nicks 20 may be included
in the shape of a die 10 but not pass through the plane of the braces 16.
Accordingly, the braces 16 do not need to be cut to clear the nicks 20. Rather
than requiring in the protocol that the input file be prepared with the nicks
deleted, step 32 may include a conversion routine that scans the input file
for
nicks 20 and replaces them with a line segment. To locate nicks 20, the nick
removing routine searches for shapes within or similar to a specification,
which may be input by the user or contained in pre-existing configuration
file,
for the shape of a nick 20. The conversion routine or program may also
account for input files that contain shape information relating to the point
of
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the cutting edge 14, as is typical. Since the point of the cutting edge 14 may
be offset from the side of the knife 12 that will contact a brace 16, this
offset
must be accounted for. A similar offset occurs where there are punches or
other items to be supported by braces 16 within a die 10. Offset relating to
these internal items may be accounted for in step 42, for example, by
increasing the size of such internal features as required by the offset.
Optionally, some functions in step 42 may be performed after the shapes of
the braces are determined. For example, the offset between the side of the
perimeter knife 12 and the point of the cutting edge 14 may be accounted for
by adjusting the shapes of the braces after they are determined.
[0043] In step 44, a die 10 to be braced is selected from the input file.
An individual die 10 can be selected, for example, by browsing through a
display of all dies 10 and selecting the desired die 10, by selecting from a
list
of alpha-numerical designations corresponding to the dies 10, or by otherwise
indicating the BLOCK number for the desired die 10. The selected die 10
may then be displayed on a screen and the user may be asked to confirm the
selection or make another selection. Once an individual die 10 has been
selected for bracing, an initialization routine clears any previous shape
information and may clear or reset appropriate parameters to default values.
The block representing the selected die is copied from the input file for more
convenient access by other routines of the bracing program. The name or
designation for the die 10 may also be copied into a file location within the
bracing program.
[0044] In step 46, parameters relevant to the number and location of
braces 16 are input. These bracing parameters may be input by the user
through the keyboard 34a in response to prompts after the die 10 is selected.
Step 46 may also be performed by other means, for example by inputting a
parameter file or including the parameters in the general input file for
extraction by the bracing program 32. Step 46 may also be performed at
other times in the process, for example, before the input file is loaded. The
bracing parameters may be based on pre-established guidelines designed to
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ensure that the bracing will be appropriate and sufficient for the intended
use
of the die 10. Sets of bracing parameters may be pre-determined for use for
various classes or types of dies 10. The classes or types of dies 10 may be
determined depending on die 10 geometry, whether there are punches or
other internal features and where they are located, mounting requirements for
the die 10, the materials used in the die 10, the type of press that the die
10
will be used with or other factors. Thus, the parameters may embody the
engineering required to produce an acceptable system of braces 16 for dies
of different shapes to be used in similar applications. Alternatively, for
10 example where most or all dies 10 to be braced will have similar
requirements, a single set of bracing parameters may be determined and
embodied in the bracing program such that step 46 becomes a part of the
working of the bracing program hidden from the user. Further alternatively,
the bracing program may be adapted to review the die 10 and determine
appropriate bracing parameters itself either by computation or by selection
from a set of previously entered or programmed bracing parameters.
[0045 The set of bracing parameters is chosen in view of the needs of
the method that will be used to determine the shape and location of the
braces. For the method to be described below, bracing parameters are as
described below.
Bracing Parameter Description
Brace Width the width of the material that the braces will be
cut from
Starting Brace Center the perpendicular distance to the edge of the die
Point from Edge of the centerline of the edge braces
The Edge Bracing Extra the maximum length of the outer edge of an
Support Length edge brace permitted when the edge brace is
located at the Starting Brace Center Point from
Edge distance
Start Brace Center from the perpendicular distance from the centerline of
Edge if Over Support an edge brace to the edge of the die to be used
parameter if the Edge Bracing Extra Support Length is
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Bracing Parameter Description
exceeded
Minimum Brace the minimum spacing between the centerlines of
Spacing adjacent edge or interior braces
Maximum Brace the maximum spacing between the centerlines of
Spacing adjacent edge or interior braces
Internal Bracing Support a length for internal edges of braces which, if
Length exceed, indicates that extra support bracing is
required
Brace Mounting Hole the diameter of the mounting holes for the
Diameter braces as modified, if appropriate, for any offsets
of a computer controlled device that will cut the
holes
Brace Mounting the distance from the edge of a brace used to
Distance from Edge determine the center points of any mounting
holes
[0046] Other parameters may also be required by the bracing program
32, and can be input at the same time as step 46 or at other appropriate
times. For example, parameters representing the offset of the point of the
cutting edge 14 to the side of the knife 12 may be entered directly or by
specifying the type of material used for the knife 12 and having the program
reference a table of offsets for different materials. Parameters representing
the offset of the cutting point and side of a punch or other internal feature
of
the die may also be entered in a similar manner. Parameters representing the
shape of nicks 20 may be entered if nicks 20 are to be identified and removed
by the bracing program. Nick parameters may include the minimum length of
one of the lines forming the nick 20, the maximum length of the nick 20 along
the die perimeter, the minimum included angle of the nick 20 or the minimum
angle formed between a first side of the nick 20 and an adjacent die 10
segment. Other parameters may also be useful for additional features in
other steps. For example, if the bracing program 32 is capable of detecting
and correcting discontinuities in the shape the die 10, a radius may be
specified for searching for adjacent un-joined line segments. Another
parameter may indicate whether holes are required or not. The various
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parameters may be entered all at one time or the parameters may be input at
multiple times dispersed throughout the overall process.
[0047] In step 48, the number and location of braces is determined.
Step 48 can be broken into various sub-steps shown in Figure 5.
[0048] Referring now to Figures 1, 3, and 5, the die 10 is checked for
any discontinuities in its perimeter at step 50. If any discontinuities are
detected, a subroutine may be invoked to search for adjacent un-joined line
segments within a specified radius and propose a method of joining the
segments. If no adjacent un-joined segment is found, or if the proposed
joinder produces unacceptable results as shown on a screen, the operator
may terminate the program. Possible discontinuities may also be dealt with as
part of step 42 or by requiring continuous shapes in the input file protocol.
[0049] In step 52, the die 10 is oriented to a reference direction. In the
following description, the reference direction is assumed to be horizontal,
although other reference directions may be used with appropriate
modification. To orient the die 10, a rectangular outline of the die 10 is
drawn
having horizontal and vertical sides touching the outer edges of the die 10.
The die 10 is fully contained within the rectangle but the rectangle is no
larger
than required to fully contain the die 10. The die 1 0 is then rotated in
increments through a specified range of rotation. At each angle, a new
rectangle is drawn and the area of the new rectangle is determined and
stored. After the die 10 has been rotated through the specified range of
rotation, the areas of the rectangles at each rotation are compared and the
die
is returned to the rotation that produced the rectangle of the smallest area.
This step may be performed fully automatically where, by drafting convention
or the input protocol, the dies 10 tend to be oriented generally horizontally
in
the input file or the range of rotation is large enough to account for
randomly
oriented dies 10. In an operator assisted variation, the operator may
initially
rotate the die 10 to a position that appears would give the smallest rectangle
or in which the features of shape of the die 10 are primarily either vertical
or
horizontal. Step 52 may then be performed as described above through a
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more limited range of rotation. Once the smallest rectangle has been found,
the die 10 is rotated again, if necessary, so that the longest side of the
rectangle of minimum area is horizontal.
[0050] In step 54, the location and shape of the edge braces 16 are
determined. This is done by first drawing two edge braces 16 of the specified
Brace Width. The centerlines of the edge braces 16 are vertical and spaced
at the Starting Brace Center Point from Edge distance from the furthest left
and right points on the die 10. The shape of the ends of the edge braces 16
is determined by intersection with the perimeter of the die 10. The length of
the outside edge of each edge braces 16 is then determined. If either edge
brace has an outside edge longer than the Edge Bracing Extra Support
Length, then that edge brace is relocated so that its centerline is at the
Start
Brace Center from Edge if Over Support distance from the furthest left or
right, as appropriate, edge of the die 10. The Start Brace Center from Edge if
Over Support distance is larger than the Starting Brace Center Point from
Edge distance since tab braces 16 may be added as described in step 58
(described below).
[0051] In step 56, the number, shape and location of interior braces 16
is determined. To do this, the horizontal distance between the centerlines of
the edge braces 16 is determined. This horizontal distance is divided into a
number of equal parts that produces the lowest number of internal braces 16
spaced between the Minimum Brace Spacing and Maximum Brace Spacing.
Internal braces 16 are drawn with their centerlines vertical and passing
through points dividing the horizontal distance into a number of equal parts.
End shapes of the internal braces 16 are determined by intersection with the
perimeter of the die 10.
[0052] In step 58, the number shape and location of any tab braces 16
is determined. To do this, the length of the outer edge of any edge brace 16
located at the Start Brace Center from Edge if Over Support distance is
determined. If this length is greater than the Edge Bracing Extra Support
Length, tab braces 16 will be provided. If so, the length is divided by the
Edge
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Bracing Extra Support Length and the resulting number is truncated to a
whole number representing the number of tab braces 16 required. The
location of these tab braces 16 along the edge braces 16 is then determined
by dividing the length of the exterior edge of the edge brace 16 by the whole
number plus one. Tab braces 16 are located with their centerlines horizontal
and passing through the division points. One end of each tab 16 is cut
square, the other is shaped by intersection with the perimeter of the die 10.
[0053] In step 60, the number, shape and location of any support
braces 16 are determined. To do this, each pair of adjacent vertical braces 16
is considered. Internal braces 16 will be considered as part of two pairs
while
edge braces 16 are only considered as part of one pair. For each pair of
braces 16, the length of the right edge of the left brace 16 and the left edge
of
the right brace 16 is determined. If either edge is longer than the Internal
Bracing Support Length, then supports 16 will be added. To locate the
support braces 16, the longer edge is divided by the Internal Bracing Support
Length and the resulting number is truncated to a whole number representing
the number of support braces 16 required for that pair of vertical braces 16.
The longer edge is then divided by the whole number plus one and support
braces 16 are added with their centerlines horizontal and passing through the
points of division. The ends of each support brace 16 has a squared off
shape. Alternate routines for providing support braces may also be used. For
example, the program may first provide supports to the right edge of the left
brace 16 of a pair and then check the left edge of the right brace of the pair
to
determine if it still has a need for more support braces 16.
[0054] In step 62, the number, location and shape of any cross-braces
is determined. To do this, the layer in the input file 33 which may contain
information about punches or other internal elements according to the
protocol is checked to determine whether there are any such elements. The
maximum dimension of any internal feature, plus any offset if appropriate, is
compared to the Brace Width. For internal features smaller than the Brace
Width, a cross brace 16 is added with its centerline oriented along the
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shortest vertical or horizontal line to any other brace 16. For larger
internal
features, two or more braces are drawn side by side to provide the required
width. For very large internal features, the user may modify the cross-bracing
determined by the program as appropriate.
(0055] In step 64, mounting holes 18, if any, are automatically placed at
the end of a brace 16 that intersects with the die 10 perimeter. Whether there
are to be any holes depends on the intended use of the die 10 as
communicated to the program by an input parameter. The bracing program 32
calculates the placement of the mounting holes 18 in the following manner: (i)
the longitudinal centerline of the brace is found to divide the brace 16 into
two
half widths; (ii) for each brace half-width, a line perpendicular to the brace
centerline through the most interior point where the half-width intersects the
die perimeter is found; and (iii) mounting holes 18 are placed at the Brace
Mounting Distance horizontally inward from the brace 16 edge vertically
inward from the line described above. The mounting holes 18 are made to
have the Brace Mounting Hole Diameter. Mounting holes 18 are also placed
at the center of a brace 16 if the brace length is greater than 10". If the
brace
length is less than 1.5" and both ends intersect with the die perimeter, two
mounting holes 18 are placed in the centre of the brace 16. When automatic
brace placement is complete, the braces are numbered or otherwise
identified.
[0056] In step 66, the bracing may be modified by the user by moving,
adding or deleting braces 16. For this purpose, the bracing scenario is shown
to the user on screen of the computer 31. The user may then add, move or
delete a brace 16 by any convenient input devices. Once relocated or added,
braces 16 are re-numbered and there may be an automatic or manual
adjustment of other braces 16, i.e. internal braces. Before permitting a brace
16 to be added or moved, the bracing program 32 may check for compliance
with location rules, such as the following rules: (i) that the brace 16 must
lie
within the die 10, (ii) the brace 16 cannot be located within a pre-existing
brace 16, (iii) the end of a brace 16 may not intersect both another brace 16
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and the die 10 exterior, and (iv) an angled brace 16 can not overlap other
braces 16, and vice versa. A request to add a horizontal or vertical brace 16
across another brace 16 may be interpreted as a request for multiple braces
16 in line. Braces 16 may be added, moved or deleted to achieve the results
as described in Figures 2B, 2D, 2E or 2F. While these modifications may be
performed by the user in the embodiment described, the program may
alternately be modified to achieve similar results.
[0057] One example of a special case is a die, such as an L-shaped
die, that does not fit the rectangular model used in the method. Such dies may
be instead separated into two rectangular regions with braces in each region
parallel to the smallest dimension of that region. The bracing program 32 may
be modified to locate L-shaped dies by comparing the lengths of successive
braces 16 and, if an increase in length beyond a parameter is found, rotating
the reference direction for an area above the last brace (before the large
increase in brace length) and re-drawing the braces for that area. Dies that
have long interior protrusions or corners need support at those corners.
Braces on these dies need to be positioned such that the interior corner is
supported. In these cases, the braces are positioned according to the method
above, but then one of the interior braces is moved until it supports the
corner
without a cutout in the brace, provided that the movement still meets the
minimum and maximum spacing rules. This can also be achieved in the
bracing program 32 by searching for these features and then moving the
closest brace towards the feature in small steps until the corner is
supported.
Then, the perimeter of the die is checked to determine if the unsupported
length of any section of knife 12 has increased such that an additional brace
is required. Large rectangular or square dies having a smallest dimension of
greater than 8 inches may be braced on all four sides with perpendicular tabs
linking the bases to the outside of the die. The perpendicular tabs should be
spaced according to the above method.
[0058 Referring again to Figures 1, 3 and 4, the shape, quantity and
location of braces 16 for a given die 10 are provided as an output in step 49.
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The output may take any convenient form. For example, the output may be
the output file 35 produced in a form suitable for further processing, such as
by the brace-making machine 38. Alternately, the bracing scenario generated
by the bracing program 32 may be presented visually, such as in a drawing
file or printed drawing of the braces 16 or of a braced die 10. Before output,
the braces 16 may be automatically numbered sequentially from left to right
and from top to bottom if not previously numbered in the program.
[0059] Figures 6-8 show the brace-making machine 38 (also referred to
as the apparatus) which preferably cuts braces 16 from strip stock (not
shown). The strip stock is typically made of steel. Strip stock suitable for
braces may come in a variety of widths ranging from about 5/$ to 2 inches or
more, a variety of thickness ranging from about ~/$ to '/4 inch and lengths,
which may be random, ranging from about 8 to 16 feet. Each strip is generally
straight, but typically has some curvature along its length in planes both
normal to and parallel with the width of the strip.
[0060] Brace-making machine 38 has a frame 102 that supports its
various components. A portion of frame 102 forms a hopper 104 that
supports a stack of strips of feed material. Hopper 104 includes vertical
barriers 106 separating the hopper from a bed 108 formed by a series of
rollers 110. The vertical barriers 106 are suspended from the frame 102 and
extend downwards but do not touch the bottom of the hopper 104. A gap
between the vertical barriers 106 and the bottom of the hopper 104 is
provided so that a single strip of material may slide through the gap while
remaining strips are retained in the hopper 104.
(0061] A series of piston assemblies 112 are mounted to the frame 102
and operable to push a strip of material onto the rollers 110.
[0062] Referring now to Figures 6 and 10, the piston assembly 112 has
a pneumatic cylinder 118 attached to a piston mounting bracket 120 for
mounting the piston assembly 112 to the frame 102. The cylinder 118 drives
a piston shaft 122 moving within a spacing block 124 that keeps the top of the
piston shaft 122 in or below the plane of the bottom of the hopper 104. An
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abutment 124 projects above the top of the piston shaft 122 to a height which
allows it to engage a single strip of material on the bottom of the hopper 104
without contacting a second strip. Actuating the pneumatic cylinder 118
causes the piston shaft 122 to extend which causes the abutment 124 to push
a strip of material onto the rollers 110.
[0063] Referring again to Figures 6-8, and to Figure 8 in particular, the
rollers 110 have flanges 114 which define a reference edge of the bed 108
and prevent the strip of material from being pushed past the reference edge.
A series of guide mechanisms 116 are mounted to the other edge of the bed
108 opposite the reference edge.
[0064] Referring now to Figures 6 and 11, the guide mechanisms 116
have a vertical roller 128 held within an angled block 130. The vertical
roller
128 is attached to the angled block 130 with a spring that biases the vertical
roller 128 towards the front of the brace-making machine 38. When the strip
of material is on the bed 108, the vertical rollers 128 apply pressure to the
edge of the strip to bias the strip of material towards the flanges 114 of the
rollers 110 of the bed 108. However, the angled block 130 is itself mounted
through a spring to a guide base 132 so that it is lowered out of the way by
the weight and pressure of a strip of material being pushed by the piston
assemblies 112 from the hopper 104 to the bed 108. The angled block 130
moves back upwards to allow the vertical rollers 128 to contact the edge of
the strip after the strip is on the bed 108. To accommodate different widths
of
strip material despite the limited range of movement of the vertical rollers
128,
the guide base 132 is mounted to the frame 102 through pins 134. A
thumbscrew 136 may be turned to slide the guide base 132 along the pins
134 to a position appropriate for strips of various widths. The spring biasing
of the vertical rollers 128 allows them to hold the strip material against the
reference edge of the bed 108 despite any longitudinal curvature of the strip
material in the plane of the width of the material.
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(0065] Referring again to Figures 6-8, and Figure 8 in particular, a
piece of strip stock on the bed 108 may be held by either of two clamps. The
first is a front clamp located at the front of the bed 108.
[0066] Referring to Figures 6 and 9, the front clamp 138 includes a
mounting bracket 140 for supporting the various parts of the front clamp 138
and for mounting the front clamp 138 to the frame 102. The front clamp 138
also has a wear plate 142 that a strip of material to be cut may rest on. A
pair
of clamping rollers 144 pass through the wear plate 142 and are attached to a
clamp actuator 146. The clamp actuator 146, when actuated, pulls the
clamping rollers 144 towards the wear plate 142 to hold a strip of material
clamped against the wear plate 142. When released, the clamping rollers 144
allow the strip of material to slide along the wear plate 142 but may be set
to
keep the strip of material near the wear plate 142 to counter any curvature of
the strip material tending to lift the strip material ofF of the bed 108. One
of the
clamping rollers 144 is attached to a thumbscrew 136 that permits the
distance between the clamping rollers 144 to be altered to accommodate strip
materials of various widths.
[0067] Referring again to Figures 6-8, the second clamp is a material
feed clamp 148 provided as part of a material feeder 150. Material feed
clamp 148 is an electromagnetic clamp positioned above the bed 108 such
that, when activated, it attaches to the strip of material on the bed 108.
Components of the bed 108, particularly the rollers 110 may be made of non-
ferrous materials, such as brass or bronze, so as to not interfere with the
operation of the material feed clamp 148. Material feed clamp 148 is attached
to a feeder arm 152 driven linearly by material feeder screw 154 along guide
156. Material feeder screw 156 is in turn driven with material feed servo 158
such that material feed clamp 148 is capable of moving in two directions,
either advancing or retracting a strip of material along the bed 108. Guide
156
ensures that the material feed clamp 148 travels linearly with minimal
deviation.
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[0068 A cutting head 160 at the front of the bed 108 includes a cutting
chamber 162, a cutting tool 164 and a cutting tool servo 166. The cutting
chamber 162 encloses a space around where the strip material is to be cut
and includes a chute 170 for large bits of material to fall through to a
receptacle (not shown). The cutting chamber 162 also includes an exhaust
port 174 for connection to an exhaust unit 172. Cutting tool 164 is a plasma
torch although other cutting tools may also be used. Cutting tool 164 is
powered by a cutting tool power supply 176. Cutting tool 164 is movable on a
slide assembly and is attached to cutting tool servo 166 such that, by
operation of cutting tool servo 166, cutting tool 164 may be moved across the
width of a strip of material placed under it by material feeder 150. Cutting
tool
servo 166 may be operated with the strip of material stationary, optionally
clamped by front clamp 138, to provide a square cut across the strip material.
Alternately, cutting tool servo 166 and material feed servo 158 may be
operated simultaneously to cut a curve or series of line segments across
width of the strip. Cutting tool vernier screw 178 allows the height of the
cutting tool 164 to be set as required above the strip of material and allows
adjustment of that height from time to time as a consumable part of the
cutting
tool 164 is consumed.
[0069 The brace-making machine 38 also has various proximity
switches 180 and other sensors. For example, two proximity switches (not
shown) are provided with each cylinder 118 to determine whether each
cylinder 118 is in either its forward or back position. Another proximity
switch
180 is provided near the material feed clamp 148 to determine whether
material is near the feed clamp 148. Another proximity switch 180 is provided
near the cutting tool 164 to determine if the strip of material is within a
known
offset from the centre of the cutting tool 164. Two more proximity switches
180 are provided near the material feed servo 158. One of these proximity
switches 180 indicates whether the material feeder 150 is in a position
representing the feed servo 158 home position. The other indicates whether
the feed servo 158 has over-traveled beyond its home position. Two more
proximity switches (not shown) are located on the cutting tool slide assembly
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and determine whether the cutting tool servo 166 is in its home position or
whether it has over-traveled. Another proximity switch 180 is located over the
bed 108 behind the material feed servo 158 to indicate whether there is a
strip
of material on the bed 108 behind the feed servo 158 home position. Sensors
(not shown) are provided, for example, to indicate whether there is sufficient
air pressure to operate the cylinders 118 or to indicate whether an emergency
stop button has been pushed. Other proximity switches or sensors may also
be provided. In addition, various wires and switches are also provided as
required to operate the various components of the brace-making machine 38.
For example, switches are provided to activate or de-activate the clamp
actuator 146, to turn the exhaust unit on or off, to turn the cutting tool 164
on
or off, to advance or retract the cylinders 118 and to engage or disengage the
material feed clamp 148. Other controls may also be provided. Many of the
components mentioned above are housed within a control cabinet 182.
[0070] The control cabinet 182 also houses some parts of a control
system 500 that controls the brace-making machine 38.
[0071] Referring now to Figures 12-14, the control system 500 includes
a programmable logic controller (PLC) 502. PLC 502 comprises a power
supply 504, a CPU 506, a servo controller 508, a communications card 510,
an input controller 512 and an output controller 514. Multiple controller or
communication cards may be used if desired. For example, there may be two
servo controllers 508, one for each servo 158, 166.
[0072] Communications card 510 connects PLC 502 to a local area
network (LAN) 516 through the use of communications hub 518. The LAN
516 communications hub is a preferred embodiment of the communication
network 36 described above and illustrated in Figure 3. In one embodiment,
the LAN 516 makes use of the ethernet protocol but any number of other
protocols may be utilized.
[0073] Referring now to Figure 3 and 12, the computer 31 directs the
actions of the PLC 502. The computer 31 preferably communicates with the
PLC 502 via LAN 516 and the hub 518. The computer 31 is adapted to store
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or receive the input file 33 describing the shape of a die and run the bracing
program 32 to produce the output file 35 describing the number and shape of
braces required to brace a particular die (as described in detail above).
[0074] In an alternative embodiment (not shown), the functions of
computer 31 may be distributed between two (or more ) computers. One
computer may run the bracing program 32 and a second computer may
control the PLC 502. In such an embodiment, the second computer may
include a database of output files 35 containing information on the shape of
braces, for example, the shapes of all braces required for a given die. The
output files are received from the first computer (which runs the bracing
program 32) in any suitable manner, such as via LAN 516.
[0075] Referring to Figures 3 and 12, an operator operates computer
31 to select or produce the output file 35 containing information regarding
the
shape of one or more braces. In one embodiment, the output file 35 contains
all required information for the brace-making machine 38 to create the braces.
The output file 35 is downloaded to PLC 502. This information is downloaded
in the form of a modified data exchange file (DXF). Other data files, not in
the
DXF format, may also be used to contain the information required for brace-
making machine 38 to cut a brace. Based upon the downloaded information,
PLC 502 then directs the brace-making machine 38 to manufacture the
required braces. As the computer 31 is connected to LAN 516, it may receive
patterns from or transmit patterns to any other device connected to LAN 516.
[0076] Computer 31 and PLC 502 are configured to operate according
to a protocol determining what information will be contained in the DXF or
other file and how it will be ordered in the file. Depending on the protocol
and
how information is input to the computer 31, it or PLC 502 or both may be
required to perform some data processing operations to produce or use the
information in the file which may include running program 32 as described
earlier. There are numerous options for the protocol that may be used
according to a users preference. In one example, the file downloaded to PLC
502 contains all information relating to the braces 16 required for a selected
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die 10. This information includes the number of braces 16 to be made, the
shape of each brace 16 and the location of any holes in each brace 16. The
shape of each brace 16 is defined in the file by a series of co-ordinates, for
example X-Y co-ordinates, for the start and end of each line segment forming
the shape of the ends of the brace 16, the co-ordinates for the centers of any
holes 18 and an overall length of each brace 16. Also included may be
various parameters such as the width of the strip of material for the braces
16,
the distance between the cutting edge 14 and interior surface of the knife 12,
the width or radius of the cut made by the cutting tool 164 and the radius of
holes 18. According to the protocol, the computer 31, or an operator using
computer 31 will have determined whether any nicks 20 pass through the
plane of the braces 16 and adjusted the shape of the braces 16 as described
in the input file accordingly. Holes 18 will be shown in the input file by the
location of their centers, but the hole diameter will be included as a
parameter. Accordingly, PLC 502 performs calculations to determine the
required path of the cutting tool 164 considering the desired center and
diameter of each hole 18 and the radius of a cut made by the cutting tool 164
in the course of instructing the servos 158, 166 to cut each hole 18. The
shape of the ends of each brace 16 will be provided as several line segments
corresponding with the shape of the cutting edge 14 of the die 10. Thus, the
computer 31 may be required to convert brace 16 or die 10 shapes originally
provided in forms other than a series of line segments. PLC 502 is required to
account for the distance between the cutting edge 14 and the interior of the
knife 12 and the radius of cut of the cutting tool 164 in the course of
instructing the servos 158, 166 to cut the ends of the braces 16. Alternately,
the computer 31 may be required to pre-process the information in the file to
account for these differences before downloading the file to the PLC 502.
Rules are also provided relating to any other features of the braces 16, for
example, to account for mounting punches or other items that may also be
attached to the braces 16. The protocol may also include rules for tagging,
ordering or arranging data, such as in blocks or layers, such that PLC 502
may locate and extract information regarding distinct braces 16. The protocol
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also includes rules regarding the scale and units to be used, for example,
that
the scale will be 1:1 and all units will be inches. The computer 31 may also
be
configured to provide other pre-processing of the input file, for example to
check for and correct any discontinuities in the shape of a brace 16, to
number distinct braces 16 or to determine the shapes of braces 16, the
location of holes 18, or other aspects of the braces 16 from other information
such as information describing the die 10, for example by running program 32
as described earlier.
[0077] The computer 31 may also be used to manually control the
brace-making machine 38. For manual control, the computer 31 provides an
interface through which an operator may view the information provided by the
inputs shown in Figure 13 and other indicators of system performance. The
computer 31 also allows an operator to direct the operation of the servos 158,
166 of Figure 13 or the outputs shown in Figure 14 individually. For example,
the servos 158, 166 may be homed or moved to a selected distance from the
home position and the outputs shown in Figure 14 or others may be turned on
or off, advanced or retraced, engaged or disengaged or activated or de-
activated. The computer 31 also allows an operator to enter commands that
may over-ride or modify an automated function on the PLC 502. For example,
an operator may stop, pause or reset an operation being performed by PLC
502 or re-set or respond to alarms. The computer 31 converts these various
commands entered by an operator into signals directing the PLC 502. The
computer 31 may also provide or alter various machine control parameters
stored in PLC 502. These parameters may include items such as travel limits
for the servos 158, 166, or desired servo speeds. These parameters may
also include various offsets such as the distance between the proximity switch
180 near the cutting tool 164 and the centre of a cut made by the cutting tool
164 or between the cutting tool 164 home proximity switch 180 and the
reference edge of the bed 108. These offsets are used by the PLC 502 to
convert information from the proximity switches 180 to information regarding
the actual location of the strip of material being cut, the cutting tool 164
or the
feed clamp 148.
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[0078] Referring again to Figure 12, each component of the PLC 502
will now be discussed in more detail. Power supply 504 provides the power
for PLC 502. CPU 506 controls the overall processing of PLC 502. Servo
controller 508 controls cutting tool servo 166 and material feed servo 158.
Cutting tool servo 166 advances or retracts cutting tool 164 and feed servo
158 advances or retracts material feeder 150. Communication card 510
connects PLC 502 to hub 518 and thus to control the computer 31. Input
controller 512 controls a plurality of inputs devices as shown in Figure 13.
Each input device determines the status of a component of the brace-making
machine 38. The inputs include a number of proxy switches 180 described
above which are grouped together in a dashed rectangle within Figure 13.
Other inputs include an air pressure switch 522 and a master control relay
emergency stop button 524. Air pressure switch 522 determines if air
pressure is sufficient to operate the cylinders 118 or any other component of
the bracing machine 38 that is pneumatically powered. Master control stop
button 524 detects whether an operator has pressed an emergency stop
button and, if so, cuts power to the machine 38. Other inputs may be added
as desired.
[0079] Output controller 514 controls a various components of the
machine 38, as shown in Figure 14. Control of these components typically
occurs through various ancillary components not shown. For example, clamp
actuator 146, exhaust unit 174, cutting tool 164 and feed clamp 148 are all
electrically powered. The output controller 514 controls these components
through various switches or relays. Cylinders 118 are pneumatically powered
and the output controller 514 controls them through an appropriate
combination of components such as relays, solenoids and valves. Other
controls may be added to provide other functions. For example, a printer may
be added to place a part or serial number on a label on each brace cut or a
cleaner may be added to clean the braces before they leave the machine 38.
Cleaning and labeling may also occur before a brace is cut.
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[0080] Figure 15 shows the cutting process 600 performed by control
system 500. In step 602, the control system 500 and brace-making machine
38 are initialized. This step includes various sub-steps to make the control
system 500 and brace-making machine 38 ready for operation. For example,
servos 158 and 166 are homed and checks are made to determine if a strip of
material is present on the bed 108 with its front edge under the cutting tool
164, if communications links are open and whether the brace-making machine
38 is ready for operation. Steps are performed to overcome any initial
deficiencies. For example, a piece of strip of material may be loaded if there
is none on the bed 108 or a strip of material on the bed 108 may be moved
forward to place its front edge under the cutting tool 164 by at least a
minimum clearance distance.
[0081] In step 604, the PLC 502 waits for the output file 35 to be
downloaded. Once a file is received, processing continues to step 606 in
which information regarding a brace 16, which may be a first or next brace 16
to be cut, is extracted. If multiple braces 16 are included in the input file
to the
PLC 502, which is the output file 35 from the computer 31, the PLC 502 will
establish an indexing log or counter indicating the total number of braces to
be cut. The counter allows PLC 502 to determine at step 620, to be described
below, whether more braces need to be cut.
[0082] In step 608, the position of the material feeder 150 is checked to
see whether it is over top of a strip of material and far enough away from the
cutting tool 164 to cut the next brace 16. If both conditions are not
satisfied,
processing moves to step 622 where the material feeder 150 is moved back
to a distance behind the cutting tool 164 at least as large as the overall
length
of the brace 16 to be cut plus a minimum operating clearance. To move the
material feeder 150, front clamp 138 is first engaged and material feed clamp
148 disengaged so that the strip of material will not move. Material feed
servo
148 is then operated to move the material feeder 150 back. In step 624, a
check is made to see if the material feeder 150 was capable of secure
sufficient strip material for the next brace 16. The check may include
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monitoring the proximity sensor 180 that determines whether the material
feeder 150 has over-traveled. Over-travel may occur if an operator attempts
to cut a brace larger than the maximum travel, less operating clearances, of
the material feeder 150. This possibility may also be avoided by having the
computer 31 or PLC 502 check any braces 16 for excess length before
attempting to cut them.
(0083] Alternately, the control system 500 may be adapted to cut larger
braces 16 by allowing the material feeder 150 to re-locate itself in relation
to a
strip being cut while cutting a single brace 16. In the present embodiment,
the
material feeder 150 holds the strip to be cut at only one location while all
cuts
are made for a brace 16.
(0084] A check is also made of the proximity sensor 180 near the
material feed clamp 148 to see if material is present to be clamped. Material
will not be present if the strip of material on the bed 108 is too short for
the
brace 16 to be cut. In this case, the process proceeds to steps 626 and 628
in which the existing material is ejected from the bed 108 and a new piece of
material is loaded. Step 626 may be performed by alerting the operator
through the computer 31 that the strip is too short. The operator then
removes the strip of material and then enters an instruction through the
computer 31 indicating that the process may proceed to step 626.
(0085] Alternately, steps 626 and 628 may be performed automatically.
For the automatic process, material feeder 150 is moved so as to be able to
grab near the back edge of the strip. Front clamp 138 is opened, material
feed clamp 148 turned on, and material feeder 150 is then moved to its
farthest forward travel limit. This moves the strip of material to a position
in
front of where a new strip to be loaded. The front clamp 138 is then closed,
the material feed clamp 148 opened and the material feeder 150 returned to
its home position. Cylinders 118 are advanced to push a new strip onto the
bed 108. Material feed clamp 148 is closed on the new strip and the cylinder
118 are retracted. Proximity switches 180 are checked to verify that all
cylinders advance and retract as required. The material feeder 150 is then
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moved forward by a pre-set distance sufficient to put the front edge if the
new
strip under the cutting tool 164 which also ejects the old strip through the
front
of the cutting chamber 162.
[0086] In step 608, the current position of the material feeder 150 is
also checked to make sure the rear or front travel limits will not be reached
when moving the steel during a cut. For this check, the peak to peak distance
of the head cut is added to the current position of the material feeder 150
and
the result checked to make sure that the limits of the material feeder 150
will
not be reached. If a limit would be reached, then the material feeder 150 is
moved without moving the feed stock as required so that the cut may be
made without requiring the material feeder 150 to be repositioned relative to
the feed in the middle of a cut.
[0087] When the checks in step 608 have been satisfied, the process
proceeds to step 610. In step 610 the head, or front edge, of the brace 16 is
cut. To make the cut, the PLC 502 generates a profile of the cut and array of
instructions to the servos 158, 166. The servos 158, 166 are moved to the
first co-ordinate in the profile. The cutting tool 164 is then turned on and
the
servos 158, 166 are run through their profile moves. The cutting tool 164 is
then turned off.
[0088] In steps 612 and 614, the control system 500 checks whether
the holes 18 are required, and if so, cuts the holes 18. To facilitate
checking
whether there are any holes to be cut, the PLC 502 notes the total number of
holes to be cut and maintains a counter as each hole 18 is cut. Each holes 18
is cut in a manner similar to that described for the cutting the head of the
brace 16. When all holes 18 are cut, the process proceeds to step 616 where
the tail of the brace 16 is cut in a manner similar to how the head of the
brace
16 was cut. As the tail is cut, the brace 16 falls through the front of the
cutting
chamber 162.
[0089] After a brace 16 is cut, material feeder 150 is moved forward to
a clearance distance sufficient to ensure that the head of the next brace 16
may be cut. The clearance distance accounts for the width of the cut made by
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the cutting tool 164. The clearance distance also accounts for the possibility
that the tail cut on the last brace may have extended forwards towards the
end of the cut and backwards from the reference edge of the bed 108. In this
case, a solid width of material is not left under the path of travel of the
cutting
tool 164 and the proximity sensor 180 near the cutting tool 164 can not be
used to determine by how much the strip needs to be advanced to correct the
problem.
[0090] The clearance distance may be set in the protocol and braces
16 that would cause a problem despite the clearance distance would not be
allowed. Alternatively, the total length of brace 16 information in the input
file
may be used to establish a clearance for each brace. Alternatively, the
computer 31 may compare the tail and head cut shapes of braces 16 and,
with consideration for the width of cut, determine a distance for the material
feeder 150 to move in step 618 and include this in the input file. In this
way,
strip material is saved since the PLC 520 may reduce the clearance distance
in cases where the tail of one brace 16 has a shape similar to the head of the
next brace 16 to be cut.
[0091] After step 618, the process continues to step 620 where the
index is consulted to see if there are more braces to cut. If so, then the
process returns to step 606. If not, then the process returns to step 604. The
process is thus continuous, but may be terminated by the operator through
the computer 31 when the operator is finished cutting braces.
[0092] Although the invention has been described with reference to
certain specific embodiments, various modifications can be made without
departing from the spirit and scope of the invention as described in the
following claims. In particular, but without limitation, the program 32 may be
modified, other forms of cutters may be used, modified systems may be used
to move the strip of material and the cutter, the configuration of the machine
may be changed, different types of clamps, actuators, guides or piston
assemblies may be used, other parts may be substituted for parts suitable for
performing the same tasks, the protocol may be changed and the series of
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steps performed may be modified. Further, although the systems and
methods have been described for use in making braces for dies, they, or parts
of them, may be adapted or used in other situations where a piece of strip
stock is designed or cut to fit to a boundary.
