Note: Descriptions are shown in the official language in which they were submitted.
z
This invention relates to couplings, of the force or
drive fit type, for joining sections of plain end pipe and pipe
pile, and provides much greater tensile strength than the pipe
coupling described and claimed in my U. S. patent No. 4,053,247,
issued October 11, 1977, now in commercial production and sold
under the trademark "MARNICK". The Marnick coupling is a
double sleeve type of coupling in which annular tapered sockets
are provided at opposite ends into which the pipe sections may
be forced or driven. The tapered sockets may be such as to
cause expansion of the end of the pipe sections as they travel
into the sockets. Also the sockets may taper inwardly to cause
reduction in diameter of the pipe as it travels into the
sockets. The Marnick coupling provides a leak-proof joint with
considerable tensile strength.
It is the purpose of this invention to provide a very
high strength force fit coupling for plain end pipe and pipe
pile which will sustain tensile forces higher than the Marnick
coupling is capable of sustaining. I refer to my new coupling
as the Wedge-Tight Coupling. The new coupling is similar in
principle to that of the Marnick coupling but differs therefrom
in that the annular tapered sockets for the pipe are formed
between two annular tapered rings disposed in concentric spaced
relation to the outer sleeve. These tapered rings are capable
of axial movement relative to the sleeve and about a central
annular shoulder or stop formed integrally or otherwise
attached to the sleeve, which forms the inner end of the
annular sockets.
As each pipe section is forced into the annular
socket of the coupling, it expands over the tapered ring in the
manner of a wedge, into tight metal-to-metal contact with the
interior conical surface of the outer sleeve. For this
coupling to yield under tension, one or both of two things must
occur, namely: (1) The outer sleeve must expand, and/or (2)
The expanded section at the end of the pipe must be reduced in
diameter. I have found that, when tested to failure, the
Marnick coupling has failed through reduction in diameter of
the expanded section of the pipe. In my new wedge-tight
coupling, the tapered rings or wedge sleeves are free to move
with the outward movement of the pipe and provide reinforcement
within the pipe to prevent the expanded pipe section from reduc-
ing in diameter. Thus, failure of the coupling under tension
can occur only by expansion of the outer sleeve along the
conical section or due to tension at the thinnest point adjacent
the center stop or ring. In my new wedge-tight coupling both of
these points can be of sufficient strength 50 that the joint
formed at the coupling can develop the full tensile strength of
the pipe with which the coupling is used.
More specifically, the invention provides a force fit
coupling for so joining two sections of plain end pipe and pipe
pile as to form a high tensile strength joint, said coupling
comprising a retaining sleeve having a radial projection there-
on and two separate wedge sleeves positioned in concentric
coaxial relation to the retaining sleeve at opposite sides of
the radial projection, each of said wedge sleeves having an
outer conical surface which matches a corresponding inner
conical surface on said retaining sleeve and abuts said radial
projection so as to provide an annular socket therebetween where-
in said sleeves are engaged ~y a pipe and pipe pile that is
driven axially therein by force to deform said pipe sections
radially, said wedge sleeves serving not only to deform the
pipe sections when driven axially into said socket but also to
strengthen them against redeformation by pull-out forces.
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The invention also provides an annular end cap for
attachment to the end of a plain end pipe section and pipe pile
to constitute reinforcement therefor, said end cap constituting
a force fit coupling of high tensile strength, said coupling
comprising a retaining sleeve having an inner conical recess
and a separate wedge sleeve positioned in concentric relation
within the retaining sleeve and having an outer conical surface
matching the inner conical recess on said retaining sleeve, to
form an annular recess therebetween, said sleeves being effec-
tive when engaged by the end of the pipe section as it is
forced axially into said recess to deform the pipe section
radially, said wedge sleeve serving not only to assist in
effecting deformation of the pipe section radially as the pipe
section is driven axially by force into said recess but also to
strengthen said pipe section against redeformation by pull-out
forces.
The invention also provides a force fit coupling for
joining two sections of reinforced precast concrete pile, said
coupling comprising a reinforcing metal sleeve attached coaxial-
ly to the end of one section of pipe pile and having an inner
conical surface with cylindrical surfaces at opposite ends
thereof, a separate wedge sleeve having an outer surface match-
ing that of the said reinforcing metal sleeve and disposed in
concentric spaced relation within said reinforcing metal sleeve
to form an annular socket, a metal pipe section on the other of
said two sections of reinforced precast concrete pile adapted
to be driven by force into said socket, said sleeves being
effective upon engagement by said pipe-section when driven by
force into said socket to cause radial deformation of the said
metal pipe section, said wedge sleeve functioning also to
support said metal pipe section and resist redeformation there-
of when the other section of precast concrete pipe is subjected
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to a tensile force tending to pull the sections of precast
pipe pile apart.
The invention also provides a force fit coupling for -
joining two plain end pipe sections of different diameters
respectively, said coupling comprising a main ring member having
two radially extending shoulders in axially separated relation,
an exterior conical surface adjacent one of said shoulders, an
interior conical surface adjoining the other of said shoulders,
and two separate metal rings, one of which is of conical shape
and concentrically surrounds said exterior conical surface in
spaced relation and abuts said one shoulder when a pipe section
is driven by force between the ring members, and the other of
which rings has an exterior conical surface matching that of
the interior conical surface and which is disposed in concentric
spaced relation to the conical surface on the said main ring and
which abuts the other of said shoulders whereby said pipe sec-
tions are deformed radially when said pipe is forced axially
between said conical surfaces.
The invention also provides a force fit coupling for
so joining two sections of plain end pipe and pipe pile as to
form a high tensile strength joint, said coupling comprising two
outer metal rings joined in end-to-end coaxial relation, a
central ring element secured interiorly of said rings at the
juncture thereof, and two separate inner metal ring elements
disposed in concentric spaced relation within said metaI rings
and movable axially so as to engage said central ring element in
abutting relation on opposite sides, the interior of said metal
rings having a conically tapered surface and the exterior of
said ring elements having a conforming conically tapered sur-
face, said outer and inner metal rings being engaged by said
pipe sections when forcefully driven axially therebetween to
effect radial deformation of said pipe sections, said separate
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ring elements also serving to support the pipe sections against
redeformation as tension force is exerted on the pipe sections
tending to pull them outwardly out of the coupling.
The couplings of the wedge-tight type may be adapted
for coupling pipe sections of different diameter, and the
expansion of the pipe may exceed twice the thickness of the
pipe made. The central ring integral with the outer sleeve may
be provided with annular steps or shoulders for c~ntering the
wedge rings or sleeves in a coaxial position with regard to the
outer sleeve.
Various preferred embodiments of the new improved
wedge-tight type of coupling constituting my present invention
are hereinafter described in detail, in connection with the
accompanying drawings, wherein:
Figure 1 is a sectional view, illustrating one embodi-
ment of my wedge-tight coupling, in which the pipe end if
expanded as the pipe is forced into the coupling;
Figure 2 is a sectional view, on a reduced scale,
illustrating an embodiment of my wedge-tight coupling in which
the pipe end is reduced in diameter as the pipe is forced into
the coupling;
Figures 3, 4, 5 and 6 are fragmental sectional views,
illustrating several embodiments of the wedge-tight coupling
for coupling two pipe sections of different diameters;
Figures 7, 8 and 9 are fragmental sectional views,
illustrating embodiments of the wedge-tight coupling, in which
expansion of the pipe in the coupling may exceed twice the wall
thickness of the pipe;
Figures 10 and 11 are fragmental sectional views,
illustrating embodiments having means for centering the wedge
sleeves or rings within the outer sleeve;
Figure 12 is a fragmental sectional view, showing an
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end ring for a pipe or pipe pile embodying a wedge-tight
coupling therein; and
Figure 13 is a fragmental sectional view, showing a
form of coupling embodying the wedge-tight principle for
coupling two sections of reinforced concrete pipe pile.
Referring to Figure 1 of the drawings, a preferred
form of coupling 10, embodying my invention is shown. This
embodiment of coupling comprises an outer sleeve 11 and two
shorter sleeves 12 and 13 disposed within the outer sleeve and
abutting opposite sides of a central projecting ring or
shoulder 14 formed integrally with the sleeve 11. The interior
of the outer sleeve varies in diameter from the outer ends to
the central ring 14. The exterior surface of the shorter
sleeves 12 and 13 and the interior surface of the outer sleeve
cooperate and are so spaced as to provide an annular pocket or
socket in which to force or drive the end of the pipe sections
15 and 16. As shown, the portion 17 of the annular sockets
adjacent the opposite ends of the coupling are flared outwardly
to assist in the entry of the pipe into the socket. The
intermediate portion 18 of the socket is of conical or tapered
form so as to cause the pipe to expand outwardly to a portion
19 of uniform or approximately uniform diameter. The portion
19 of the socket is preferably made of a length which is
greater than the thickness of the socket.
The outer diameter of the shorter sleeves 12 and 13
is slightly less than the smallest internal diameter at the
portion 17 of the sockets. Thus, prior to installation of the
pipe sections into the coupling, the sleeves 12 and 13 may be
moved in and out of the coupling as well as diametrically and
concentrically. In order to hold the sleeves temporarily in
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position prior to installation of the pipe, strips of adhesive
tape 20 are applied circumferentially interiorly of the short
sleeves 12 and 13 in bridging relation to and contacting the
central ring 14. These adhesive strips may be removed after
the installation of the pipe sections into the coupling.
It should be understood that while the coupling 10
may be employed to join pipes of any diameter, it is especially
adapted for joining sections of pipe of relatively large
diameter, such as pipe of 3 to 4 feet in diameter. Various
methods may be employed for forcing or driving the pipe
sections into the annular sockets of the couplings 10, as for
example impaction or by "jacking" in the manner described in my
copending application Serial No. 967,965, filed December 11,
1978.
As shown in Figure 1, one of the pipe sections 15 is
shown in position prior to entry into the annular socket of the
coupling, while the other pipe section 16 is shown in position
as driven fully into the socket into contact with the central
stop ring 14.
Referring to Figure 2, a modification of the coupling
10 is shown and designated by the reference character 10'.
Coupling 10' differs from coupling 10 in having an inner sleeve
11', and two relatively short sleeves or wedges 12' and 13'
which concentrically surround the sleeve at opposite ends and
which axially abut opposite sides of a radially outwardly
projecting ring 14' integrally or otherwise attached to the
sleeve 11'. In this coupling, the outer surface of the sleeve
11' and the interior surfaces of the sleeve 12' and 13'
cooperate and are so spaced as to provide annular sockets .into
which the pipe sections 15' and 16' may be forced or driven.
5.
762
In the coupling 10' the annular sockets differ from
the annular sockets in coupling 10 in that they comprise an
annular portion 17' at the outer end which serves as an entry
to the socket, an intermediate conical portion 18' which
differs from the conical portion 18 in that the diameter of the
socket reduces instead of expanding, and a final portion 19' of
minimum uniform diameter. Preferably, the portion 19' is
longer in length than the thickness of the socket or the wall
thickness of the pipe sections 15' and 16'.
While not shown, it will be understood by analogy to
Figure 1, that adhesive strips, similar to adhesive strips 20
of Figure 1, may be provided for holding the three sleeves 11',
12' and 13' together prior to installation of the pipe sections
15' and 16'. Similarly to Figure 1, pipe section 15' is shown
in a position ready for entry into the annular socket at one
end of the coupling 10', while pipe section 16' is shown in
position as fully driven into the annular socket at the other
end of the coupling.
Referring now to Figures 3, 4, 5 and 6, various
similar embodiments of couplings are shown for joining two pipe
sections 21 and 22 of different diameters respectively. Figure
3 discloses a coupling 23 comprising a main ring member 24 and
two auxiliary ring members 25 and 26. The auxiliary ring
member 25 is tapered uniformly from end to end and concen-
trically surrounds a correspondingly tapered or conical outer
surface 27 at one end of ring member 24. Similarly, auxiliary
ring member 26 has a tapered annular surface on the exterior
thereof that concentrically surrounds a conical surface 28 at
the opposite end of ring member 24. The annular sockets
provided between each of the ring members 25 and 26, and the
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ring member 24 are such as to cause reduction in diameter and
expansion, respectively, of the pipe sections 21 and 22 as they
are driven into their respective sockets. The annular inwardly
sloping shoulder 27(a) on the top of ring member 24 is adapted
to receive impact blows from a mandrel. It will be noted also
that the main ring member 24 is formed with offset flat annular
surfaces 29 and 30 which serve as stops ~or the auxiliary ring
members 25 and 26 respectively, as the pipe sections 21 and 22
are driven into the couplings.
Figure 4 discloses a coupling 33 comprising a main
ring member 34 and two auxiliary ring members 35 and 36
concentrically surrounding respective, conical surfaces 37 and
38 at opposite ends of the ring member 34. Coupling 33 differs
from coupling 23 in that the innermost part 39 and 40 of the
annular sockets formed between the auxiliary ring members and
the main ring member 34 is cylindrical in form. The portions
39 and 40 have a length substantially in excess of the wall
thickness of pipe sections 21 and 22.
Figure 5 shows a coupling 43 which is a variation of
the coupling 33. It comprises a main ring member 44 which
differs from ring member 34 in having an upper annular portion
with an internal conical surface 45 terminating in a cylin-
drical surface 46. An auxiliary ring member 47 is disposed
within the conical surface 45 and has an exterior conical
surface 48 conforming to the conical surface 45, and a
cylindrical surface 49 conforming to the cylindrical surface
46. Thus, there is formed between the auxiliary ring member 47
and the surfaces 45 and 46 on the main ring member 44 an
annular pocket into which the pipe section 21 may be driven.
The lower portion of the main ring member 44 has an
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internal conical surface 50 terminating in a cylindrical
surface 51 similarly to the lower portion of the riny member
34, and an auxiliary ring member 52 disposed concentrically
within the surfaces 50 and 51 to form an annular pocket into
which a pipe section 22 may be driven.
Figure 6 shows a coupling 53 similar to the coupling
43 except that it comprises a main ring member made in two
parts 54 and 55 provided with female and male threads
respectively, by which the two parts are joined together.
Coupling 53 also comprises two auxiliary ring members 56 and 57
disposed, similarly to the ring members 47 and 52, concentric-
ally within corresponding conical and cylindrical surfaces.
Figures 7, 8 and 9 show variations of a force fit
coupling which enables deformation, that is expansion of the
pipe sections as they are driven into the coupling by an amount
which exceeds twice the wall thickness of the pipe sections.
Figure 7 shows a coupling 60 comprising two external
ring members or sleeves 61 and 62 having threads 63 internally
thereof and joined by an exteriorly threaded ring member 64 on
which the ring members 61 and 62 are screwed into butting
contact. The internal surface of each of the ring members 61
and 62 comprises a conical, flared outer portion 65, a conical
mid-portion 66 extending from this portion 65 toward the
threaded ring member 64, and a cylindrical portion 67 extending
to the threads 63.
Two auxiliary ring members 68 and 69 are disposed
concentrically within the interior surface of the two exterior
ring members 61 and 62. The exterior surface of the ring
members 68 and 69 conform to the interior surfaces 65, 66 and
67 of the outer ring members 61 and 62 so as to provide an
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annular socket therebetween into which the pipe sections 70 and
71 may be respectively driven or forced.
It will be noted that the slope of the conical sur-
faces 66 is such that the pipe sections will be expanded more
than twice the thickness of the pipe sections. It will be
further noted that the outer ring mebers 61 and 62 must be
assembled on the ring member 64 after the internal ring members
68 and 69 are disposed endwise into the outer ring members.
This is the case because the diameter of the auxiliary ring
members 68 and 69 is larger than the diameter of the flared
openings in the outer ring members and could not be assembled
endwise into the outer ring members 61 and 62 after they are
joined together on ring 64.
The coupling shown in Figure 8 is quite similar to
that of Figure 7 and corresponding parts will be identified by
the same reference numerals as in Figure 7 without additional
description. The coupling in Figure 8 differs from that in
Figure 7 in that the innermost portion of the annular sockets
formed between the outer ring members 61, 62 and the inner ring
members 68, 69 is not cylindrical but is conical and is tapered
inwardly toward the ring 64. Thus, the ends of the pipe
sections 70, 71 are reduced in diameter after being expanded in
diameter. Thus, under tension, the pipe sections grip the
inner ring members 68 and 69 which thus provide corresponding
internal support for the ends of the pipe sections and resist
collapse of the pipe sections.
The coupling shown in Figure 9 is similar to that of
Figure 7 but, to avoid repetitious description, elements in
Figure 9 will be identified by corresponding reference numerals
with the prime (') suffix. The outer ring members 61' and 62'
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and inner ring members 68' and 69' may be machined parts.
Moreover, the central ring member 64' and the two outer ring
members 61' and 62' are assembled as by a circumferential weld
75.
Figures 10 and 11 show two variations of a similar
form of coupling, and corresponding elements in the two Figures
will be referred to by the same reference numeral except in
Figure 11 a prime (') suffix will be used. Referring to the
drawings, these couplings comprise an outer sleeve 80,81' and
two internal shorter sleeves 81,81' and 82,82'. The outer
sleeve 80,80' has an internal projection ~33,83' extending
radially inward from the wall of the outer sleeve. The
projection 83,83' is stepped to provide a shoulder 84,84'
having a radius slightly larger than the outer diameter of the
inner sleeves, whereby the inner sleeves are centered concen-
trically within the outer sleeve in spaced relation. In the
coupling of Figure 10, the interior surface of the outer sleeve
80, at opposite ends of the sleeve, comprises a tapered or
flared surface 85, a conical mid-portion 86 and an inner
cylindrical surface 87 of uniform radius. The inner sleeve 81
has an outer surface with a contour matching that of the outer
sleeve to provide an annular socket which expands from a flared
entrance to a cylindrical portion of unform radius.
In the coupling of Figure 11, the internal surface of
the outer sleeve differs in contour from that of Figure 10 and
comprises a conical or flared surface 85', a surface 88 of
uniform radius and relatively short length, a tapered or
conical surface 86', and a cylindrical surface 87' of uniform
radius terminating at the projection 83'. The outer surface of
the inner sleeves 81', 82' has a contour matching that of the
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interior surface of the outer sleeve 80'.
Pipe sections 90 and 90' are shown in Figures 10 and
11 respectively in position for entry into the annular socket
of the couplings.
The form of coupling shown in Figure 11 is somewhat
stronger under tension than that of Figure 10 by reason of the
portion of the annular socket of uniform radius between the
outer flared portion and the inner conical portion. It will be
seen that when the coupling of Figure 11 is subjected to
tension to the point of ultimate failure, the length of the
surface 88 of the outer sleeve provides a greater amount of
metal which must be expanded by pulling the wedge reinforced
pipe section out of the coupling.
Referring to Figure 12, a form of the invention is
shown which is adapted as a reinforcement for the end of an
open-end pipe pile 91. As shown, an end cap or fitting 92 for
the end of the pipe pile section 91 comprises an outer sleeve
portion 93, and an inner wedge or sleeve portion 94. The
annular socket formed between the outer and inner sleeve
comprises an outer flared portion 96, a portion 97 of uniform
radius, a conical portion 98 which expands to a cylindrical
portion 99 of uniform radius.
Figure 13 shows an adaptation of the wedge-tight
principle of the invention to a coupling for reinEorced precast
concrete pipe pile. The coupling 100 for the two concrete pipe
pile sections 101 and 102 comprises an outer sleeve or ring 103
welded circumferentially at 104 to the end plates 105 of the
pipe pile section 101 and an inner or wedge sleeve 106 which
has an outer surface matching the inner contour of the outer
sleeve 103.
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The pipe pile section 102 has an end plate 107 to the
outer face of which is welded a short section 108 of pipe pile.
As will be apparent, the pipe pile section 108 is
forced or driven into the annular socket of the coupling 100 to
effect a coupling o~ the two pipe pile sections. While not
shown, it will be understood that the wedge sleeve 106 may be
held temporarily in position by an auxiliary means, similar to
the adhesive strips 20 of the coupliny in Figure 1.
While specific embodiments of the invention have been
shown and described, it will be understood that variations
therein are possible within the terms of the following claims.
