Cutting – Processes – Plural cutting steps
Reexamination Certificate
2003-01-10
2004-11-09
Goodman, Charles (Department: 3724)
Cutting
Processes
Plural cutting steps
C083S414000, C083S417000, C083S409200, C083S444000, C083S437200
Reexamination Certificate
active
06813982
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general to a positioner and cutting apparatus. More specifically, the present invention relates to an automatic conduit cutting apparatus for the Heating, Ventilating and Air Conditioning (HVAC) industry, wherein a plurality of conduits are cut to optimum lengths to provide internal reinforcements of ducting.
BACKGROUND OF THE INVENTION
Ductwork is utilized to facilitate the heating, ventilation and cooling of various buildings, both residential and commercial. The ductwork typically comprises individual duct sections which are then coupled together to form a continuous, largely airtight duct for conveying a moving mass of air.
The duct sections are typically made from strong, yet relatively light, material such as sheet metal, or the like. It is an important design characteristic that the duct remain as lightweight as possible in order to minimize the size and weight of fasteners and other structural components required to support the ductwork, as well as maintaining materials and fabrication costs of the ductwork itself at reasonable costs.
Commonly utilized ductwork often have rectangular, circular or oval cross sections, and are frequently manufactured and supplied in pre-cut lengths or sections with transversely outwardly protruding interconnection flanges provided at opposite longitudinal ends of the section, to facilitate interconnecting duct sections at a job site, and thus form the finished air conveying ducts of desired lengths.
Whatever the size or shape of the ductwork, the relatively small thickness of the walls of the ductwork, as compared to its cross-sectional dimensions, results in the duct walls being rather flexible. Conventional ductwork may therefore experience large, possibly destructive and oftentimes loud structural deformations if static or dynamic air pressure differentials between the interior and the exterior of the ductwork exceeds a predetermined threshold value. For this reason, mechanical engineering standards (e.g., standards written by the Sheet Metal and Air Conditioning Contractor's National Association or SMACNA), as well as most building codes, require that certain ductwork be reinforced against expansion and/or collapse.
These reinforcements can be either internal or external. External reinforcements may be accomplished by using various structural shapes such as bars, angle iron or the like. Internal reinforcements generally include structures, such as conduit or threaded rods, that span the width or height of the ducting and are attached to the ducting side walls.
One known internal reinforcement mechanism for ductworks is shown in FIG.
1
and includes a threaded tie rod
2
oriented between opposite planar sides of a rectangular duct
4
. Fixed, inner washers
6
are disposed adjacent the interior side of the opposing duct walls
4
, while exterior washers
8
are disposed on the exterior of the duct walls
4
in matching relation to one another. As shown in
FIG. 1
, a threaded nut
10
is screwed down against each of the exterior washers
8
to secure the reinforcing tie rod in position.
There are several variations of the reinforcing mechanism shown in FIG.
1
and these variations may also include rubber O-rings or other elastic sealing devices disposed between the washers and the duct walls. Moreover, it is also known to replace the fixed, inner washers
6
with threaded nuts or lock nuts which may then be tightened in association with the tightening of the exterior threaded nuts
10
to provide the necessary rigidity to the reinforcing mechanism.
FIG. 2
illustrates a cross-sectional view of another known internal reinforcing mechanism which is comprised of a metallic tube
10
and an insert
12
. After the insert
12
has been disposed within the tube
10
, the tube
10
is crimped so as to deform in a radially inward direction. The crimped section of the tube
10
becomes locked within an annular groove
14
which has been inscribed about the periphery of the insert
12
, thus locking the insert
12
within the tube
10
. A threaded bolt
14
extends from the insert
12
and would extend beyond the exterior of a duct wall to be secured thereto via a threaded nut, or the like. The insert
10
may also include an inner cavity to accommodate an unillustrated biasing member, such as a spring, wherein the spring would outwardly bias the bolt
16
for greater flexibility. The insert
12
may be made from a metallic material or from a plastic or polymer material.
FIGS. 3 and 4
illustrate two embodiments of cross-sectional views of an internal reinforcing mechanisms as described in Patent Application No. 60/412,722, titled “Duct Reinforcement Rod”, filed on Sep. 23, 2002 and incorporated herein in its entirety by reference. As depicted in
FIG. 3
, the reinforcing rod
20
includes a metal tubing or conduit
22
and a standard bolt or jam nut
24
. As illustrated in
FIG. 3
, the conduit
22
and the bolt
24
are sized so that the head
26
of the bolt
24
enjoys a tight fitting relationship with the inner diameter of the tubing
22
when the conduit
22
is pressed over the head
26
. It will be appreciated that the length of the threaded section of the bolt
24
extends beyond the conduit
22
and may be varied in accordance with the specific design characteristics of the ductwork and the relative length of the bolt
24
utilized. Additionally, both a first and a second crimp,
30
and
32
respectively, are disposed above and below the head
26
to ensure against longitudinal movement of the bolt
24
within the conduit
22
.
FIG. 4
illustrates an internal reinforcing rod
40
utilizing a threaded nut
42
in place of the bolt
24
shown in FIG.
3
. As depicted in
FIG. 4
, the conduit
22
is pressed over the nut
42
and the conduit
22
. In similar fashion to
FIG. 3
, both a first and a second crimp,
30
and
32
respectively, are disposed above and below the nut
42
to ensure against longitudinal movement of the nut
42
within the conduit
22
.
Prior art software is generally utilized to determine the ductwork requirements for an entire project or job, such as the ductwork required in the construction of a new building. Problematically however, internal reinforcement requirements, such as size, quantity and length of conduits or the like, are not included in prior art software packages.
Moreover the raw materials, such as the threaded rod or conduit used in the reinforcement mechanisms illustrated in
FIGS. 1-4
, are generally sold in lengths that far exceed the assembled lengths of the reinforcement mechanisms. For example, ½ inch or ¾ inch nominal diameter conduit is generally sold in 10 foot lengths. Accordingly, even after the internal reinforcement requirements are calculated, the net lengths of each reinforcement must be cut from the 10 foot lengths of raw conduit. This can not only be a very time consuming and expensive process, it can also generate a lot of wasted conduit if care is not taken to determine the optimum cut lengths per 10 foot length based on the particular reinforcement requirements of a job. This problem of generated waste can be especially problematic for larger jobs, such as the construction of a large building.
With the forgoing problems and concerns in mind, it is the general object of the present invention to provide a conduit cutting apparatus which overcomes the above-described drawbacks while maximizing effectiveness and flexibility, and minimizing waste in the assembling process.
SUMMARY OF THE INVENTION
The present invention offers advantages and alternatives over the prior art by providing a computerized positioning and cutting apparatus for automatically cutting structures to predetermined lengths with a minimum amount of scrap for a given project. The apparatus includes a frame. A positioning trough is supported by the frame. A magazine is mounted to the frame, which is sized to receive uncut lengths of structure to be selectively fed to the positioning trough. A drive system is mounted to the frame and opera
Blum Richard Frank
Shah Ashok
Goodman Charles
McCormick Paulding & Huber LLP
Met-Coil Systems Corporation
LandOfFree
Positioner and cutting 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 Positioner and cutting apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Positioner and cutting apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3339270