U.S. patent application number 10/666173 was filed with the patent office on 2004-04-22 for elongate receiver tube and method of making the same.
Invention is credited to Palmer, David H..
Application Number | 20040075245 10/666173 |
Document ID | / |
Family ID | 26791471 |
Filed Date | 2004-04-22 |
United States Patent
Application |
20040075245 |
Kind Code |
A1 |
Palmer, David H. |
April 22, 2004 |
Elongate receiver tube and method of making the same
Abstract
A receiver tube for a trailer hitch assembly including a hollow
metal tube stock wherein the receiving end thereof is provided with
a cold formed reinforcing flange formed of the outermost end of the
tube stock is folded upon itself.
Inventors: |
Palmer, David H.;
(Jonesville, MI) |
Correspondence
Address: |
MACMILLAN SOBANSKI & TODD, LLC
ONE MARITIME PLAZA FOURTH FLOOR
720 WATER STREET
TOLEDO
OH
43604-1619
US
|
Family ID: |
26791471 |
Appl. No.: |
10/666173 |
Filed: |
September 19, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10666173 |
Sep 19, 2003 |
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10096231 |
Mar 12, 2002 |
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60284050 |
Apr 16, 2001 |
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Current U.S.
Class: |
280/495 |
Current CPC
Class: |
B60D 1/485 20130101 |
Class at
Publication: |
280/495 |
International
Class: |
B60D 001/00 |
Claims
What is claimed is:
1. An elongate receiver tube for a trailer hitch assembly
comprising: a hollow elongate tube having an internal rectangular
cross-section and having a first end adapted to receive a trailer
hitch bar having a complimentary outer rectangular cross-section,
the first end of said tube having an integral reinforcement
construction wherein the first end of said tube is provided with an
outwardly extending fold formed of substantially two thicknesses of
the tube, wherein the outermost end portions are folded against one
another by a cold forming process to form a peripheral outwardly
extending fold at the first end of said tube, the cold forming
process includes the use of a clamp to hold an unfolded portion of
the tube and wherein the entire cross-section of the clamp is
rectangular, the fold having an inner dimension which is
substantially the same as an inner dimension of said tube and an
outer dimension greater then an outer dimension of said tube.
2. The receiver tube according to claim 1, wherein the fold has a
flat face spaced from the first end formed against an outer wall of
the clamp.
3. The receiver tube according to claim 1, wherein the fold has a
substantially rounded outer surface.
4. An elongate receiver tube for a trailer hitch assembly
comprising: a hollow elongate tube having an internal rectangular
cross-section and an external rectangular cross-section, said tube
having a first end adapted to receive a trailer hitch bar having a
complimentary outer rectangular cross-section to be slidably
received in the internal rectangular cross-section of said tube,
the first end of said tube having an outwardly extending flange
portion formed by a cold forming process, the flange portion formed
wholly outside of a clamping structure, wherein a side of the
flange facing away from the first end abuts a wall of the clamping
structure which is external of the clamping structure, the flange
provided with an outwardly extending fold formed of substantially
two thicknesses of the tube, the flange portion having an inner
dimension which is substantially the same as an inner dimension of
said tube and an outer dimension greater then an outer dimension of
said tube.
5. The receiver tube according to claim 4, wherein the flange
portion has a substantially rounded outer surface.
6. An elongate receiver tube for a trailer hitch assembly
comprising: a hollow elongate tube having an internal rectangular
cross-section and an external rectangular cross-section, said tube
having a first end adapted to receive a trailer hitch bar having a
complimentary outer rectangular cross-section to be slidably
received in the internal rectangular cross-section of said tube,
the first end of said tube having a fold with a substantially
rounded outer surface, the fold formed by a cold forming process
wherein a clamping structure with an internal surface having a
rectangular shape over its entire length is used, the flange
portion formed wholly outside of the internal surface of the
clamping structure, the fold formed of substantially two
thicknesses of the tube, the flange portion having an inner
dimension which is substantially the same as an inner dimension of
said tube and an outer dimension greater then an outer dimension of
said tube.
7. The receiver tube according to claim 6, wherein a side of the
fold facing away from the first end has a flat face formed against
a wall of the clamping structure, the wall being external of the
clamping structure.
Description
[0001] This application is a divisional patent application of U.S.
patent application Ser. No. 10/096,231, filed Mar. 12, 2002, which
claims the benefit of U.S. provisional patent application Serial
No. 60/284,050, filed Apr. 16, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a trailer hitch assembly
and more particularly to an elongate receiver tube for a trailer
hitch assembly and a method of making the same.
[0004] 2. Description of the Prior Art
[0005] Trailer hitches employed in conventional motor vehicles
include a receiver tube permanently affixed to the motor vehicle
and is adapted to receive a removable trailer hitch bar. The
receiver tube is typically affixed to the vehicle frame and may
include additional cross bracing. The exposed end of the receiver
tube is open to receive the removable trailer hitch bar. A mounting
ball adapted to receive a trailer tongue is typically mounted on
the exposed end of the trailer hitch bar.
[0006] The exposed end of the receiver tube is exposed to
considerable lateral and up and down forces during use. In order to
compensate for these forces, the ends of the receiver tubes have
been reinforced. Such reinforcement includes the use of a
reinforcement ring which is slid over the end of the receiver tube
end and welded in place. Such a welded construction includes a weld
bead which is a corrosion site adversely affecting the life cycle
of the assembly.
[0007] Another method has been developed wherein the trailer hitch
receiver tube end was reinforced by a metal forming process. The
process is carried out with a tube stock at an elevated temperature
of about 1800.degree. F. and was upset to form a reinforcement bead
around the entire peripheral of the tube. The process is referred
to as a "hot upset" operation.
[0008] It is an object of the present invention to produce an
elongate receiver tube wherein the exposed end is reinforced by a
cold forming process to form a crimped reinforcement flange
thereon.
[0009] Another object of the invention is to produce a method for
cold forming a crimped flange on the end of the elongate receiver
tube for a trailer hitch assembly.
SUMMARY OF THE INVENTION
[0010] The above, as well as other objects and advantages of the
invention may be readily achieved by an elongate receiver tube and
method for making the same wherein the elongate receiver tube for a
trailer hitch assembly comprises an elongate tube having an
internal rectangular cross-section and having one end adapted to
receive a trailer hitch bar having a complimentary outer
rectangular cross-section, the one end of the tube having an
integral reinforcement construction wherein the end of the tube is
provided with an outwardly extending fold formed of two thicknesses
of the tube including the outermost end portions are folded against
one another by a cold forming process to form a peripheral
outwardly extending fold at the end of the tube, the fold having an
inner dimension which is the same as the inner dimension of the
tube and an outer dimension greater then the outer dimension of the
tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The objects and advantages of the invention will become
readily apparent to those skilled in the art from considering the
following detailed description of an embodiment of the invention in
the light of the accompanying drawings, in which
[0012] FIG. 1 is a fragmentary perspective view of a trailer hitch
assembly incorporating the features of the present invention;
[0013] FIG. 2 is an enlarged fragmentary perspective view of the
receiver tube incorporating the present invention as illustrated in
FIG. 1; and
[0014] FIG. 3 is a cross-sectional elevational view of a portion of
the tooling required to form the reinforcement at the end of the
elongate receiver tube illustrated in FIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Referring to the drawings, there is illustrated a trailer
hitch assembly generally indicated by reference numeral 10. The
trailer hitch assembly 10 typically includes an elongate receiver
tube 12, and cross members 14 and 16, connected to respective
vehicle frame members 18 and 20.
[0016] The receiver tube 12 is provided with a hollow interior 22,
as clearly illustrated in FIG. 2 which receives a trailer hitch
bar, not shown. The trailer hitch bar is slid into the interior of
the receiver tube 12 until a connecting hole 24 formed in the
receiver tube 12 is aligned with a corresponding hole in the hitch
bar to receive an appropriate locking pin. The outwardly projecting
end of the trailer hitch bar is typically provided with a mounting
ball adapted to support the tongue of an associated trailer.
[0017] The construction of the receiver tube 12 includes a
reinforcement flange 26, which extends completely around the
outermost peripheral edge. The reinforcement flange 26 is best
illustrated in FIG. 3 wherein it is shown that the reinforcement
flange 26 is formed of two thicknesses of the wall of the tube 12
including the outermost end portion 28 which is folded against
another thickness 30. The resultant reinforcement includes the
peripheral outwardly extending flange 26 formed of the thicknesses
28 and 30 folded on themselves at the end of the tube 12. The
reinforcement flange 26 has an inner dimension which is the same
and typically slightly larger than the inner dimension of the tube
12 and an outer dimension greater than the outer dimension of the
outer surface of the tube 12.
[0018] The formed reinforcement flange 26 adds strength to the end
of the receiver tube 12 to assist in withstanding the stresses
applied thereto by the associated trailer hitch bar during use.
[0019] The reinforcement flange 26 is formed by a cold metal
forming process wherein the tube stock used to form the receiver
tube 12 is placed in a clamp 32 to secure the outside surface to a
predetermined length. Next, a single punch having the same cross
sectional configuration as the interior of the receiver tube 12 to
be strengthened is inserted into the hollow interior of the tube
12. The outer surfaces of the punch are effective to support the
tube 12 during the following cold forming crimping process. It will
be understood that one end of the tube stock extends beyond the
clamp 30 to provide sufficient length of unsupported tube stock to
form the desired strengthening crimped reinforcement flange 26.
[0020] Next, a punch is further inserted into the interior of the
receiver tube 12 to commence formation of the crimped reinforcement
flange 26. The punch is advanced into the hollow tube interior
causing equal wall thicknesses in the end portion of the tube 12 to
be forced against the clamp 30 causing the unsupported tube end to
be trapped outside of the clamp 30 thus preventing the equal wall
thickness of the receiver tube from being deformed during the cold
forming process. The punch is caused to continue the inward
movement until a circumferentially outwardly extending shoulder of
the punch meets the unsupported end of the tube 12 and continues
until the unsupported tube stock folds outwardly to a developed
limit. When the limit is reached, the punch continues and causes
the material of the receiver tube 12 to buckle and fold inwardly
upon itself until the desired cross-sectional configuration is
achieved. The movement of the punch is stopped and the punch is
withdrawn.
[0021] It has been surprisingly determined that the cold formed
folded upon itself reinforcement flange 26 including the metal
stock thicknesses 28 and 30 has increased reinforcement and life
cycle characteristics to any other known receiver assemblies.
[0022] In accordance with the provisions of the patent statutes,
the present invention has been described in what is considered to
represent its preferred embodiment. However, it should be
understood that the invention can be practiced otherwise than as
specifically illustrated and described without departing from its
spirit or scope.
* * * * *