U.S. patent number 3,655,297 [Application Number 05/092,646] was granted by the patent office on 1972-04-11 for coupling for foldable tubular parts.
This patent grant is currently assigned to Magnetic Forming Corporation. Invention is credited to Hugh R. Bolen, Jr., Charles S. Wiggins.
United States Patent |
3,655,297 |
Bolen, Jr. , et al. |
April 11, 1972 |
COUPLING FOR FOLDABLE TUBULAR PARTS
Abstract
A coupling for the elongated tubular shaft of a paddle, or the
like, made of two lengths of tubing, the coupling incorporating a
hinge that is retractible into the shaft when the elongated shaft
is in use, the joint between the two parts of the shaft becoming
then a splice between the ends of the tubing without external
fastenings.
Inventors: |
Bolen, Jr.; Hugh R. (Lexington,
VA), Wiggins; Charles S. (Lexington, VA) |
Assignee: |
Magnetic Forming Corporation
(N/A)
|
Family
ID: |
22234328 |
Appl.
No.: |
05/092,646 |
Filed: |
November 25, 1970 |
Current U.S.
Class: |
416/72; 403/100;
135/74; 403/102 |
Current CPC
Class: |
F16C
11/10 (20130101); Y10T 403/32393 (20150115); Y10T
403/32409 (20150115) |
Current International
Class: |
F16C
11/10 (20060101); F16C 11/04 (20060101); F16c
011/00 () |
Field of
Search: |
;287/98,99 ;135/46F
;416/72 ;115/24.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kundrat; Andrew V.
Claims
I claim:
1. In a foldable paddle or the like having a handle at one end and
a blade at the other end and an elongated tubular shaft comprising
at least two lengths of tubing connecting said handle and blade, a
solid double-ended fixed plug, a first end of which is secured in
the end of one of said tubing lengths and the second end of which
extends a considerable distance outwardly therefrom to form a plug
fitting snugly but slidable into the end of the said second of said
tubing lengths, at least one shallow slot like recess extending
into the end of the said second end of said double-ended fixed
plug, said recess being formed to present diverging walls at right
angles to each other diverging toward the end of said second end, a
slidable plug in said second of said tubing lengths, at least one
slot like recess in said slidable plug complementary to the recess
in said second end of said fixed plug, and of the same angular
shape, at least one flat angular hinge link pivotally secured in
said recesses in said slidable plug and in said fixed plug, said
angular link being formed on one edge with portions lying at right
angles to each other to engage one wall of each of said recesses
when said hinge link is moved to one extreme position, and the
other edge being formed with portions parallel to corresponding
portions of said one edge lying at right angles with each other to
engage the other wall of each of said recesses when said hinge link
is moved to the other extreme position, a retaining bolt extending
coaxially of said slidable plug inwardly of said second tubing
length from said slidable plug, said retaining bolt including a
first threaded portion adjacent said slidable plug, an elongated
body portion of reduced diameter extending therefrom, and a second
threaded portion at the extremity of said bolt remote from said
slidable plug, and a nut threaded to operatively engage said
threaded portion secured in said second tubular length, said nut
being positioned in said second tubular length at a distance from
its end such that said nut acts in cooperation with said first
threaded portion to forceably pull said second end of said fixed
plug into said second tubular length, the elongated body portion of
said bolt being of a length so that when the outward edge of said
slidable plug is even with the end of said second tubular length,
said second threaded portion acts, in cooperation with said nut, as
a stop to prevent further outward axial movement of said slidable
plug.
2. The paddle of claim 1, in which said slidable plug is provided
with an annular groove, and an O-ring is provided in said annular
groove providing a waterproof seal with said second tubing length,
whereby said second tubing length cannot fill with water to destroy
the buoyancy of the paddle.
Description
This invention relates to a coupling for foldable devices,
including elongated parts where the coupling must be strong under
bending stress when in use, but which must be readily foldable for
storage when not in use.
For purposes of disclosure, this invention is described as applying
to a paddle such as might be used to propel a canoe or an emergency
inflatable boat, but it is to be understood that many other devices
may also incorporate the coupling of the invention.
Heretofore, it has been suggested that oars, which are a special
form of paddle, be made with a hinge joint in their shafts so that
the blade could be folded back to be adjacent the loom in order to
save storage space. Such an oar is illustrated in the Griffenberg
U.S. Pat. No. 1,036,222 of 1912, where a link is pivoted at one end
to the loom end of the oar and at the other end to the blade end of
the oar and where, to hold the oar in its usable condition, an
elongated sleeve encloses the link and a portion of the oar shaft
on each side of the link. This oar has not proved to be
practical.
A bolt having discontinuous threads has been proposed for a folding
tool handle as seen the Sudek U.S. Pat. No. 1,737,275, but this
handle is not subjected to bending movements when in use.
The objects of this invention are to provide a foldable coupling or
the like, that while readily foldable, has great strength when in
extended condition and can be readily assembled and
disassembled.
In general, these objects are obtained by a novel hinged joint
between the end of tubular elements forming the shaft of the
paddle.
The means by which the objects are obtained are described more
fully with reference to the accompanying drawing in which:
FIG. 1 is a view, partly in section, of the joint in a folding
paddle, the joint being shown in the position to permit
folding.
FIG. 2 is a view similar to FIG. 1, with the joint tightened to
hold the paddle rigid for use.
FIG. 4 is an end view looking down on the joint, folded in the
manner shown in FIG. 3.
FIG. 5 is a general view of the paddle.
The paddle illustrating the use of the present invention has a
blade at one end and a handle at the other, which are shown only in
FIG. 5. The shaft of the paddle is of tubing of sufficient diameter
and wall thickness to withstand the bending stresses to which a
paddle handle is subject when in use.
The tubular shaft is made in two parts, the joint between the two
parts being midlength of the paddle when in use.
Tubular element 10 may be considered to be the end of the paddle on
which the blade is mounted and tubular element 12 may be considered
to be the handle end of the paddle. A plug element 14 extends into
tubular portion 12 where it is fixed by any suitable means such as
annular indentation extending into a groove in plug 14. It will be
noted that the fit of plug 14 must be very tight in tube 12 to give
the strongest joint. An extension 14A of plug 14 extends outwardly
from a flange 14B that lies tight against the end of tubular
element 12. Extension 14A is of a diameter to fit snugly into the
end of tubular portion 10 and is of considerable length to extend
quite far into tubular element 10 to support it and give maximum
rigidity to the joint when the paddle is in use.
At the end of extension 14A are at least one, and preferably three,
recesses 16 extending in parallel planes across the end of the
extension. In a less preferred device, recesses 16 could be slots
or saw kerfs. Angular links 18 are pivoted centrally of recess 16.
The ends of links 18 lying at right angles to each other.
It will be noted that the ends of recesses 16 be at right angles to
each other, and the ends of links 18 be at right angles to each
other so that the sides of links 18 contact the ends of recesses 16
in extended condition as seen in FIG. 1 and in folded condition as
seen in FIG. 3.
A plug 20 is slidably mounted in tubular element 10. The end of
plug 20 is provided with parallel recesses 22 similar to recesses
16 and complementary to recesses 16, in which links 18 are also
pivoted. An O-ring 24 is preferably mounted in a groove about plug
20 to exclude water from tubular element 10.
A nut 26 is fixed within tubular element 10 at a considerable
distance from its end. A bolt 28 having two threaded portions 30
and 32 extends from the inner end of plug 20. The portion of bolt
28 between the threaded portions having a diameter slightly less
than the root diameter of the threads so that when the nut lies
between the threaded portions the bolt may slide through it.
From FIG. 1 it will be seen that the length of bolt 28 and the
position of nut 26 is such that when the outer end of plug 20 is
flush with the end of tubular element 10, the threaded portion 30
is at the inner side of nut 26 and prevents the inadvertent
disassembly of the paddle. As the plug 20 is thrust into tubular
element 10 to place the paddle in usable condition, the threaded
portion 32 will contact nut 26 to prevent direct axial movement of
the plug 20 into element 10. The length of bolt between threaded
portions 30 and 32 is such that when the axial movement of the plug
20 is stopped by contact of threaded portion 32 with nut 26,
tubular element 10 has enveloped most of extension 14A of plug 14.
The edge of tubular element 10 at this point must be a distance
from flange 14B slightly less than the axial length of threaded
portion 32 so that as threaded portion 32 enters nut 26 upon
relative rotation between tubular elements 10 and 12, tubular
element 10 is pulled strongly against flange 14B to assure a very
strong joint as seen in FIG. 2.
As noted above, the threaded portion 30 prevents inadvertent
disassembly of the paddle, but in the original fabrication and
assembly it will be understood that relative rotation of tubular
element 12 carrying plug 14, hinge links 18 and slidable plug 20
with the bolt 28, when it is thrust into tubular element 10, is all
that is required to assembly the paddle. As seen in FIG. 1,
disassembly can be effected by unscrewing threaded portion 30
through nut 26. While the invention has been described as having
but the one hinged joint, it is clear that two, or even more, such
hinged joints could be provided so that any length of paddle, or
other elongated device, may be folded into a desirable compact
package. If such a joint should be placed at a location where the
user's hand would normally grasp the shaft, the handle grip 34 may
be frictionally slidable along the shaft.
It will be noted that links 18 are generally curved so that, as
seen in FIG. 3, no slots are required in tubular element 10, nor
does plug 20 need to extend beyond the end of tubular element 10
when the paddle is folded.
* * * * *