U.S. patent application number 14/934897 was filed with the patent office on 2017-05-11 for floating draw plug and method of drawing tube.
The applicant listed for this patent is Penn Aluminum International LLC. Invention is credited to James Dailey, James Martin, Aaron Norris, Matt Snyder, Jake Wougamon.
Application Number | 20170128993 14/934897 |
Document ID | / |
Family ID | 58662702 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170128993 |
Kind Code |
A1 |
Norris; Aaron ; et
al. |
May 11, 2017 |
Floating Draw Plug and Method of Drawing Tube
Abstract
A floating draw plug for shaping tube comprises a necking body
and a rib forming member. The necking body has an axis and a
trailing end portion. The trailing portion has a cross-section that
is symmetric about the axis and that converges toward the axis as
it extends downstream. The rib forming member comprises helical
protrusions and helical grooves. The helical protrusions and the
helical grooves are aligned with the axis. The rib forming member
is connected to the necking body in a manner such that at least a
portion of the helical protrusions and at least a portion of the
helical grooves extend downstream of the trailing portion of the
necking body and such that the rib forming member is free to rotate
about the axis relative to the necking body.
Inventors: |
Norris; Aaron; (Herrin,
IL) ; Dailey; James; (Murphysboro, IL) ;
Martin; James; (Murphysboro, IL) ; Snyder; Matt;
(Murphysboro, IL) ; Wougamon; Jake; (Murphysboro,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Penn Aluminum International LLC |
Murphysboro |
IL |
US |
|
|
Family ID: |
58662702 |
Appl. No.: |
14/934897 |
Filed: |
November 6, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21C 3/16 20130101; B21C
1/24 20130101; B21C 37/207 20130101 |
International
Class: |
B21C 1/24 20060101
B21C001/24; B21C 3/16 20060101 B21C003/16 |
Claims
1. A floating draw plug for shaping tube, the draw plug comprising:
a necking body, the necking body having an axis and a trailing end
portion, the trailing end portion having a cross-section that is
symmetric about the axis and that converges toward the axis as it
extends downstream; and, a rib forming member, the rib forming
member comprising helical protrusions and helical grooves, the
helical protrusions and the helical grooves being aligned with the
axis, the rib forming member being connected to the necking body in
a manner such that at least a portion of the helical protrusions
and at least a portion of the helical grooves extend downstream of
the trailing portion of the necking body and such that the rib
forming member is free to rotate about the axis relative to the
necking body.
2. A floating draw plug in accordance with claim 1 wherein the
helical protrusions have a constant radius from the axis as they
extend downstream.
3. A floating draw plug in accordance with claim 1 wherein the
necking body has an axial downstream recess and a portion of rib
forming member extends therein.
4. A floating draw plug in accordance with claim 1 wherein the rib
forming member is attached to the necking body via a threaded
fastener.
5. A floating draw plug in accordance with claim 4 wherein the
necking body has an axial through-hole and a shaft member extends
through the axial through-hole in a manner connecting the rib
forming member to the necking body, and the shaft member is
configured and adapted to rotate relative to at least one of the
necking body and the rib forming member.
6. A floating draw plug in accordance with claim 1 wherein the
necking body has a leading end portion that diverges from the axis
as it extends downstream.
7. A floating draw plug in accordance with claim 6 wherein the
necking body has an intermediate cylindrical portion that extends
axially between the leading portion and the trailing portion of the
necking body.
8. A method of drawing tube in a manner forming internal helical
protrusions in the tube, the method comprising: floating a draw
plug inside the tube, the draw plug comprising a necking body and a
rib forming member, the necking body having an axis and a trailing
end portion, the trailing end portion having a cross-section that
is symmetric about the axis and that converges toward the axis as
it extends downstream, the rib forming member comprising helical
protrusions and helical grooves, the helical protrusions and the
helical grooves being aligned with the axis, the rib forming member
being connected to the necking body in a manner such that at least
a portion of the helical protrusions and at least a portion of the
helical grooves extend downstream of the trailing portion of the
necking body and such that the rib forming member is free to rotate
about the axis relative to the necking body; and pulling the tube
through a die and radially between the draw plug and the die in a
manner forming the internal helical protrusions into the tube.
9. A method of drawing tube in accordance with claim 8 wherein the
rib forming member rotates about the axis relative to the necking
body as the tube is drawn.
10. A method of drawing tube in accordance with claim 9 wherein the
die forces the tube radially inward toward the axis against the
helical protrusions and into the helical grooves as the tube is
drawn.
11. A method of drawing tube in accordance with claim 8 wherein the
helical protrusions have a constant radius from the axis as they
extend downstream.
12. A method of drawing tube in accordance with claim 8 wherein the
necking body has an axial downstream recess and a portion of rib
forming member extends therein.
13. A method of drawing tube in accordance with claim 12 wherein
the rib forming member is attached to the necking body via a
threaded fastener.
14. A method of drawing tube in accordance with claim 8 wherein the
necking body has an axial through-hole and a shaft member extends
through the axial through-hole in a manner connecting the rib
forming member to the necking body, and the shaft member is
configured and adapted to rotate relative to at least one of the
necking body and the rib forming member.
15. A floating draw plug in accordance with claim 8 wherein the
necking body has a leading end portion and an intermediate
cylindrical portion, the leading end portion diverges from the axis
as it extends downstream, and the intermediate cylindrical portion
that extends axially between the leading portion and the trailing
portion of the necking body.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
APPENDIX
[0003] Not Applicable.
BACKGROUND OF THE INVENTION
[0004] Field of the Invention
[0005] The present invention pertains to a floating draw plug for
forming internal helical ribs in tubing and a method of using the
same. More particularly, the present invention pertains to a draw
plug having a rib forming portion that is axially tethered to but
rotationally disjoined from the necking portion of the draw
plug.
[0006] General Background
[0007] Floating draw plugs are commonly used to reduce the diameter
of tubing. Float drawing, as opposed to rod or fixed plug drawing,
allows for infinite lengths of tubing to be drawn since no tooling
needs to extend axially out of the tubing. Depending upon the pull
forces and angles of taper, pulling a tube between a draw plug and
die can increase or decrease the wall thickness of tubing. In some
cases it is desirable to form internal ribs/protrusions into tubing
by floating draw plug methods. Such ribs/protrusions create grooves
that can guide fluid through the tubing. Axially aligned
ribs/protrusions also facilitate the manufacturing of
tube-inside-tube (double-wall) products. Such products can serve
well as heat exchangers. But internally ribbed tubing can also
serve well as single-wall heat exchangers. However, tubing with
axially aligned ribs/protrusions do not necessarily provide the
optimal flow-path for fluids. In some cases, it is ideal to have
tubing with helical internal ribs, but forming internal helical
ribs using drawings methods has been a challenge. To form internal
helical ribs into tubing using a draw plug, the draw plug or tubing
necessarily needs to rotate about the tubing's lengthwise axis.
When drawing long lengths of tubing, it is not practical to rotate
the tubing (e.g., if it's coming off of a coil spool). However, the
friction created by the radial forces of draw forming tubing
inhibits the rotation of any draw plug.
[0008] The present invention allows helically ribbed tubing to be
formed efficiently by draw plugs.
SUMMARY OF THE INVENTION
[0009] The invention allows for internally helically ribbed tubing
to be formed efficiently by draw plugs by rotationally disjoining
the forming of the helical ribs from the primary radial necking of
the tubing via a multi-part draw plug. With the invention, the
frictional forces suspending the necking body of the draw plug
upstream of the die do not prevent the rotation of the rib forming
member.
[0010] In one aspect of the invention, a floating draw plug for
shaping tube comprises a necking body and a rib forming member. The
necking body has an axis and a trailing end portion. The trailing
portion has a cross-section that is symmetric about the axis and
that converges toward the axis as it extends downstream. The rib
forming member comprises helical protrusions and helical grooves.
The helical protrusions and the helical grooves are aligned with
the axis. The rib forming member is connected to the necking body
in a manner such that at least a portion of the helical protrusions
and at least a portion of the helical grooves extend downstream of
the trailing portion of the necking body and such that the rib
forming member is free to rotate about the axis relative to the
necking body.
[0011] In another aspect of the invention, a method of drawing tube
forms internal helical protrusions in the tube. The method includes
floating a draw plug inside the tube. The draw plug comprises a
necking body and a rib forming member. The necking body has an axis
and a trailing end portion. The trailing end portion has a
cross-section that is symmetric about the axis and that converges
toward the axis as it extends downstream. The rib forming member
has helical protrusions and helical grooves. The helical
protrusions and the helical grooves are aligned with the axis. The
rib forming member is connected to the necking body in a manner
such that at least a portion of the helical protrusions and at
least a portion of the helical grooves extend downstream of the
trailing portion of the necking body and such that the rib forming
member is free to rotate about the axis relative to the necking
body. The method further comprises pulling the tube through a die
and radially between the draw plug and the die in a manner forming
the internal helical protrusions into the tube.
[0012] Further features and advantages of the present invention, as
well as the operation of the invention, are described in detail
below with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0013] FIG. 1 depicts a side view of a preferred embodiment of a
draw plug in accordance with the invention, with the leading
portion being oriented toward the right and the trailing end
portion being oriented toward the left.
[0014] FIG. 2 depicts an exploded assembly view of the draw plug
shown in FIG. 1.
[0015] FIG. 3 depicts a perspective partial cut-away view of the
draw plug in use.
[0016] FIG. 4 depicts a side view of the partial cut-away view
shown in FIG. 3.
[0017] Reference numerals in the written specification and in the
drawing figures indicate corresponding items.
DETAILED DESCRIPTION
[0018] A floating draw plug 10 in accordance with the invention is
shown in FIGS. 1-4. The floating draw plug 10 comprises a necking
body 12 and a rib forming member 14. The necking body 12 has an
axial trailing end portion 16, an intermediate portion 18, and a
leading end portion 20 that is symmetric about the axis of the draw
plug 10. The trailing end portion 16 having a cross-section that is
symmetric about the axis and that converges toward the axis as it
extends downstream. The intermediate portion 18 is cylindrical and
aligned with the axis. The leading end portion 20 diverges from the
axis as it extends downstream. The necking body 12 also has an
axial through-hole 22 and a counter-sunk axial recess 24 at its
trailing end. The axial recess 24 extends partially into the
trailing end portion 16.
[0019] The rib forming member 14 comprises helical protrusions 26
and helical grooves 28. The helical protrusions 26 and helical
grooves 28 preferably have a constant radius about the axis. Like
the necking body 12, the rib forming member 14 also comprises an
axial through-hole 30.
[0020] The rib forming member 14 is operatively connected to the
necking body 12 via a bolt 32 having a head 34, a shaft 36, and a
threaded end 38. The bolt 32 extends through the through-hole 22 of
the necking body 12 and the through-hole of the rib forming member
14. Preferably, a pair of nuts 40 threaded onto the threaded end 38
of the bolt 32 to thereby secure the necking body 12 and rib
forming member 14 together in a manner such that the necking body
and rib forming member aren't highly compressed against each other.
As such, the necking body 12 and rib forming member 14 can easily
rotate relative to each other, but are tied axially. Of course
there are numerous other ways to achieve the same.
[0021] In use, the draw plug 10 is inserted into an end of tubing
42 and positioned upstream of a die 44 as the tube is drawn
downstream sandwiched between the draw plug and die. The die 44 has
a through-hole 46 that has a frustoconical leading portion 48 and a
cylindrical trailing portion 50. The leading portion 48 of the
through-hole 46 of the die 44 converges as it extends downstream in
a manner preferably concentric to the trailing end portion 16 of
the draw plug 10 and has an upstream entry diameter slightly larger
than the original outside diameter of the tubing 42 being drawn.
The diameter of the intermediate portion 18 of the draw plug 10 is
just slightly less than the original inside diameter of the tubing
42. Thus, axial friction between the floating draw plug 10 and the
tubing 42 forces the draw plug toward the fixed die 44 as the
tubing is drawn through the die. The frustoconical leading portion
48 of the through-hole 46 of the die 44 necks the tubing 42 down as
the tubing passes through the die. The cylindrical trailing portion
50 of the through-hole 46 of the die 44 is slightly larger in
diameter than the helical protrusions 26 of the rib forming member
14, but nonetheless is small enough to radially compress the tubing
42 against the helical protrusions 26 and into the helical grooves
28 of the rib forming member, thereby deforming the internal
surface of the tubing in a manner such that internal helical ribs
52 are formed in the tubing. As the helical ribs 52 are formed, the
rib forming member 14 rotates relative to the necking body 12. This
decouples the large circumferential frictional forces acting on the
necking body 12 due to the radial compressive forces between the
necking body and the frustoconical leading portion 48 of the die 44
from the rib forming member 14. Thus, it is not necessary for the
necking body 12 to rotate as the helical ribs 52 are formed in the
tubing 42. This greatly reduces to rotational resistance acting on
the rib forming member 14 and thereby forms very uniform and clean
internal helical ribs 52 into the tubing 42.
[0022] In view of the foregoing, it should be appreciated that the
invention has several advantages over the prior art.
[0023] As various modifications could be made in the constructions
and methods herein described and illustrated without departing from
the scope of the invention, it is intended that all matter
contained in the foregoing description or shown in the accompanying
drawings shall be interpreted as illustrative rather than limiting.
Thus, the breadth and scope of the present invention should not be
limited by any of the above-described exemplary embodiments, but
should be defined only in accordance with the following claims
appended hereto and their equivalents.
[0024] It should also be understood that when introducing elements
of the present invention in the claims or in the above description
of exemplary embodiments of the invention, the terms "comprising,"
"including," and "having" are intended to be open-ended and mean
that there may be additional elements other than the listed
elements. Additionally, the term "portion" should be construed as
meaning some or all of the item or element that it qualifies.
Moreover, use of identifiers such as first, second, and third
should not be construed in a manner imposing any relative position
or time sequence between limitations. Still further, the order in
which the steps of any method claim that follows are presented
should not be construed in a manner limiting the order in which
such steps must be performed, unless such an order is inherent or
explicit.
* * * * *