U.S. patent number 3,699,635 [Application Number 05/040,683] was granted by the patent office on 1972-10-24 for internal line-up clamp for pipe lines.
Invention is credited to Edmund G. Bradley, Reginald P. Whittingham.
United States Patent |
3,699,635 |
Bradley , et al. |
October 24, 1972 |
INTERNAL LINE-UP CLAMP FOR PIPE LINES
Abstract
An internal line-up clamp which incorporates a pair of
interconnected but independently operable clamping assemblies, each
of which includes a set of radially movable pipe engaging shoes
adapted to clampingly engage the inner circumferences of a pair of
pipe sections in the zones adjacent their ends. At least two
axially movable pneumatic actuators are operatively associated with
each set of clamping shoes in a manner such that axial movement of
the actuators effects radial movement of the shoe set with which
they are associated. The clamping assemblies are interconnected by
a plurality of axially extending rods which are adapted to maintain
the assemblies in axial alignment while permitting them to be moved
axially with respect to each other a limited distance. A fifth
pneumatic actuator means is provided for effecting such reciprocal
axial movement of the clamp assemblies. This invention relates to a
line-up clamp for use in the welding of pipelines and, more
particularly, to a pipe line-up clamp for clamping the internal
surfaces of a pair of adjacent pipe ends and positioning and
maintaining the pipe ends in precisely aligned relationship for
welding by either manual or automatic welding means. In the
construction of pipelines, a large number of individual pipe
sections are welded together in end-to-end relationship. It is the
usual practice to utilize an internal line-up clamp to align
adjacent pipe ends prior to welding and maintain them in aligned
position during the welding operation. Many such internal pipe
line-up clamps are known and in commercial use. However, the known
clamps are deficient in many respects. For effective welding,
particularly with automatic welding equipment, the pipe ends must
not only be coaxial but the pipe walls must be accurately aligned
around their entire circumferences. Steel pipe sections used in the
pipeline construction industry are not always exactly cylindrical
nor are the ends precisely square. Also, during transportation to
and handling on the job site, the pipe sections are often bent out
of round. As a result, when a set-in pipe section is positioned in
end-to-end relationship with the open end of the welded-in portion
of the pipeline, the adjacent pipe ends often exhibit different
degrees of roundness and, also, the end faces do not abut even
though the pipes may be coaxial. Conventional line-up clamps are
generally not capable of exerting a sufficiently great pressure
upon the adjacent ends of out-of-round pipe sections to bring them
into precise alignment, particularly in the case of the relatively
large diameter pipes which are becoming increasingly common in the
pipeline industry. In addition, in using the prior art clamps it is
often difficult to bring the end faces of the pipe sections in to
proper abutting relationship since the set-in pipe is positioned
entirely by mechanical means external to the clamp itself, e.g. by
manipulation of the set-in pipe support sling and movement of the
side-boom tractor carrying the set-in pipe. This procedure, of
course, is tedious and time consuming particularly where the end
faces of pipe sections are not exactly square. For these reasons
particularly, the prior art line-up clamps are generally unsuitable
for use in conjunction with automatic welding equipment which
requires extremely precise alignment of the pipe ends and,
preferably, accurate spacing between the adjacent surfaces which
are to be joined. The prior clamps also are are generally difficult
to manipulate and position within the pipeline section preparatory
to clamping each new section in place for welding. Moreover,
difficulty is often encountered in moving the prior line-up clamps
through curved pipe sections because of the very small clearance
normally provided between the pipe engaging clamping shoes and the
internal surfaces of the pipe. Although many attempts have been
made to overcome the foregoing and other disadvantages of the prior
art clamps, non, as far as is known, has been provided which has
been entirely satisfactory in commercial operations. Accordingly,
it is an object of the present invention to provide an apparatus
for axially aligning adjacent pipe ends which is capable of
exerting very high radial forces on the inner circumference of the
pipe ends to force each into a truly circular configuration.
Another object of the invention is the provision of apparatus for
aligning pipe ends which is capable of clamping the end of a set-in
pipe and drawing it into abutting, axially aligned relationship
with the pipe end to which it is to be joined. Another object of
the invention is to provide an internal pipe line-up clamp which
may be quickly and automatically positioned and clamped at the end
of the welded in-pipe section in position for receiving the set-in
pipe section. Still another object of the present invention is to
provide a pipe line-up clamp which functions to (a) securely clamp
and round out the open end of the welded-in pipe in an initial
clamping action, (b) clamp the set-in pipe end after it is brought
into rough end-to-end alignment with the welded-in pipe, (c) draw
the set-in pipe towards the welded-in pipe to bring the end faces
of the two pipes into engagement, (d) securely clamp and round out
the end of the set-in pipe in a secondary clamping action and,
finally, (e) back-space the end face of the set-in pipe a
predetermined distance of the welded-in pipe end face to provide a
uniform gap between the adjacent pipe end faces while still
maintaining the pipe walls in accurate alignment. Yet another
object of the present invention is the provision of apparatus for
aligning pipe ends which incorporates pipe-engaging clamping
elements capable of relatively large retractive radial movement
from an operative to a non-operative position thereby permitting
the clamp to traverse curved pipe sections without damage to the
pipe or clamping elements. A still further object of the invention
is to provide apparatus for positioning and aligning pipe ends
which is relatively inexpensive to manufacture, simple to operate
and rugged and durable in use. According to the invention, these
and other objects and advantages are obtained by an internal
line-up clamp which incorporates a pair of interconnected but
independently operable clamping assemblies, each of which includes
a set of radially movable pipe engaging shoes adapted to clampingly
engage the inner circumferences of a pair of pipe sections in the
zones adjacent their ends. At least two axially movable pneumatic
actuators are operatively associated with each set of clamping
shoes in a manner such that axial movement of the actuators effects
radial movement of the shoe set with which they are associated. The
clamping assemblies are interconnected by a plurality of axially
extending rods which are adapted to maintain the assemblies in
axial alignment while permitting them to be moved axially with
respect to each other a limited distance. A fifth pneumatic
actuator means is provided for effecting such reciprocal axial
movement of the clamp assemblies. The double actuator means
associated with each set of pipe engaging shoes enables each shoe
set to be actuated independently and it also permits imposition of
clamping forces which can be selectively increased through at least
two stages to a level sufficiently great to round out large
diameter, high strength pipe sections without difficulty. In a
preferred embodiment of the clamp, the high clamping force
capability of the compound actuator means is transmitted to the
pipe engaging clamping shoes by means of a plurality of tandem
pivot links which are adapted for retraction radially inwardly when
the clamp is in a non-operative or pipe-traversing state, thus
ensuring ample clearance between the clamp shoes and the inner wall
of the pipe through which it is traversed. An another preferred
aspect, the clamp incorporates pneumatically actuated drive means
for propelling the clamp axially forwardly through a pipeline
section together with associated control means for automatically
stopping, reversing and positioning the clamp at the open end of
the welded-in pipe section in position to receive the next set-in
pipe section. The invention is explained in detail hereinbelow by
reference to a specific clamp apparatus incorporating the features
of the invention. Such apparatus is not meant to be limiting
inasmuch as it will be understood that it constitutes but one of
the ways in which the principles of the invention may be
applied.
Inventors: |
Bradley; Edmund G. (Gormley,
Ontario, CA), Whittingham; Reginald P. (Markham,
Ontario, CA) |
Family
ID: |
21912349 |
Appl.
No.: |
05/040,683 |
Filed: |
May 26, 1970 |
Current U.S.
Class: |
29/252; 228/44.5;
269/34; 29/272; 269/17; 269/48.1 |
Current CPC
Class: |
B23K
37/0531 (20130101); Y10T 29/53917 (20150115); Y10T
29/5383 (20150115) |
Current International
Class: |
B23K
37/053 (20060101); B23p 019/04 (); B23q 003/18 ();
B25b 001/18 () |
Field of
Search: |
;269/17,34,48.1
;29/252,272,282,2P |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Morse, Jr.; Wayne A.
Claims
What we claim as new and desire to protect by Letters Patent of the
United States is:
1. A line-up clamp for aligning a pair of pipeline sections by
engagement with their inner surfaces which comprises: a first set
of radially movable pipe engaging shoes adapted to engage the inner
circumference of the first of said pair of pipeline sections, a
second set of radially movable pipe engaging shoes adapted to
engage the inner circumference of the second of said pair of
pipeline sections, a first housing substantially coaxial with said
first set of pipe engaging shoes and a second housing substantially
coaxial with said second set of pipe engaging shoes, means
interconnecting said first and second housings and maintaining said
housings in axial alignment while enabling limited axial movement
of said housings with respect to each other; actuator means for
effecting reciprocal axial movement of said first and second
housings with respect to each other; first and second pairs of
fluid driven actuators mounted for reciprocatory movement in said
first and second housings, first and second drive members
operatively associated with said first and second actuator pairs
respectively and adapted for reciprocal axial movement
independently of each other, a first set of link members operably
interconnecting said first drive means with said first set of
clamping shoes such that axial movement of said drive means is
converted to radial movement for actuation of said first set of
pipe clamping shoes, a second set of link members operably
interconnecting said second drive means with said second clamping
shoe sets such that axial movement of said drive means is converted
to radial movement for actuation of said second set of pipe
clamping shoes.
2. An internal line-up clamp as claimed in claim 1 in which said
interconnecting means includes a fifth actuator means adapted to
effect selective axial displacement of said first housing and
associated set of pipe engaging shoes with respect to said second
housing and associated set of pipe engaging shoes whereby said
pipeline sections may be moved into and away from end abutment with
each other.
3. A clamp as claimed in claim 1 in which said links are arranged
and constructed for radial retraction and extension to
non-operative and operative positions respectively.
4. A clamp as claimed in claim 1 which additionally comprises drive
means for driving said clamp axially forward through said pipeline
section, control means for controlling the operation of said drive
means, backstop means comprising a radially movable cam member
adapted to normally abut said inner surface of said pipeline
section, means urging said cam member radially outwardly, means
sensitive to radial outward movement of said cam member radially
outwardly beyond said inner surface of said pipe section and
adapted on such movement of said cam member to reverse said drive
means to drive said clamp rearwardly a predetermined distance.
5. An internal line-up clamp as claimed in claim 3 in which said
links have pivotally connected inner and outer sections, and means
being provided to maintain each of said inner sections in radially
alignment with their respective outer section and to permit said
inner and outer sections to pivot with respect to each other
whereby said pipe engaging members may be retracted substantially
radially inwardly.
6. An internal line-up clamp as claimed in claim 5 including
pneumatic actuator means operatively connected with said links and
adapted to selectively pivot said links into radial alignment.
7. An internal line-up clamp for aligning a pair of pipeline
sections by engagement with their inner surfaces which comprises an
elongated axial cylindrical member, a first set of radially movable
pipe engaging members adapted to engage the inner circumference of
the first of said pair of pipeline sections, a second set of
radially movable pipe engaging members adapted to engage the inner
circumference of the second of said pair of pipeline sections, a
first sleeve circumscribing and axially slidable along said axial
cylindrical member, first actuator housing means circumscribing
said axial cylindrical member in a fixed position with respect
thereto, first and second actuator means in said first housing
means and connected with said first sleeve for effecting reciprocal
axial movement of said first sleeve along said axial cylindrical
member, a first set of generally radial linkages interconnecting
said first sleeve and said first set of radially movable pipe
engaging members such that axial movement of said first sleeve
effects radial movement of said first set of pipe engaging members,
a second sleeve circumscribing and axially slidable along said
axial cylindrical member, second actuator housing means
circumscribing said axial cylindrical member and axially movable
with respect thereto, third and fourth actuator means in said
second housing means and connected with said second sleeve for
effecting reciprocal movement of said second sleeve along said
axial cylindrical member, a second set of generally radial linkages
interconnecting said second sleeve and said second set of radially
movable pipe engaging members such that axial movement of said
second sleeve effects radial movement of said second set of pipe
engaging members, a plurality of circumferentially spaced axially
extending rod elements interconnecting said first and second
actuator housings and maintaining them in axial alignment while
permitting limited axial movement of said housings with respect to
each other, and fifth actuator means connected with said axial
cylindrical member and adapted to effect reciprocal axial movement
of said cylindrical member with respect to said second actuator
housing means.
8. The clamp as claimed in claim 7 including adjustable stop-block
means associated with said axially extending rod elements and
adapted for limiting axial movement of said rod elements such that
the first housing and associated first set of clamp engaging
members may be backspaced a predetermined distance from the second
housing and associated second set of pipe engaging members by
extension of said fifth actuator.
9. An internal line-up clamp as claimed in claim 7 in which said
first, second, third, fourth and fifth actuator means are
independently operable whereby actuation of said first and second
actuator means effects secure engagement of said first set of pipe
engaging members with said first of said pair of pipe sections,
whereby actuation of said third actuator means causes limited
frictional engagement of said second set of pipe engaging members
with said second of said pair of pipe sections, whereby subsequent
actuation of said fifth actuator causes relative axial movement of
said first and said second sets of said pipe engaging members until
said pair of pipe sections are in at least partial joint end
abutment, whereby subsequent relative axial movement of said first
and said second sets of pipe engaging members continues until said
pair of pipe sections are in substantially peripherally complete
end abutment with any necessary sliding movement of said second of
said pair of pipe sections with respect to said second set of pipe
engaging members and whereby actuation of said fourth actuator
means in a final clamping operation effects secure engagement of
said second set of pipe engaging members with said second of said
pair of pipe sections whereby said second and said first pipe
sections are securely held in end-abutting relationship.
10. The internal line-up clamp as claimed in claim 9 in which means
are provided whereby actuation of said fifth actuator effects axial
separation of said securely held end-abutting section to provide a
uniform gap of predetermined width between said pipe sections.
11. An internal line-up clamp as claimed in claim 7 including drive
means for driving said clamp axially forwardly through said pipe
section, control means for controlling the operation of said drive
means and for controlling the operation of said radially movable
pipe engaging members, end-sensing means comprising a radially
movable member adapted to normally abut the inner surface of said
pipeline section, means urging said end-sensing means radially
outwardly, means sensitive to radially outward movement of said
end-sensing means radially outwardly beyond said inner surface of
said pipeline section and adapted, on such movement of said
end-sensing means, to actuate said drive means to prevent further
forward movement of said clamp axially through said pipeline
section.
12. An internal line-up clamp as claimed in claim 11 in which said
means sensitive to said radial outward movement of said end-sensing
means beyond said inner surface of said pipe section is also
adapted, on such movement of said end-sensing means, to actuate
said first and second actuators for clampingly engaging said first
set of pipe engaging members with said first pipe section.
Description
In the drawings, wherein like reference numerals indicate line
parts in the various views:
FIG. 1 is a perspective view of an embodiment of the clamp
apparatus of the invention, with some parts omitted for sake of
clarity, showing the clamp traversing a pipe section;
FIG. 2 is a side elevation, with some parts omitted and portions
broken away, showing the clamp in operative position in a pair of
adjacent pipe sections;
FIG. 3 is a partial longitudinal sectional view taken along the
line 3--3 of FIG. 1;
FIG. 4 is a longitudinal sectional view similar to FIG. 3 but with
the pipe clamping shoes and supporting linkages in a retracted
position for travel through a pipe section;
FIG. 5 is a transverse sectional view, with portions broken away,
taken along the line 5--5 of FIG. 3.
FIG. 6 is a detail exploded perspective view of a clamp shoe
supporting link assembly;
FIG. 7 is a fragmentary longitudinal sectional view showing one
form of clamping shoe configuration;
FIG. 8 is a fragmentary longitudinal sectional view showing another
form of clamping shoe configuration;
FIG. 9 is a transverse sectional view along the lines 9--9 of FIG.
2;
FIG. 10 is a longitudinal view along the line 10--10 of FIG. 9;
FIG. 11 is a longitudinal view along the line 11--11 of FIG. 9;
FIG. 12 is an end elevation view along the line 12--12 of FIG.
11;
FIG. 13 is a side elevation detail, with portions broken away,
showing the clamp back-stop mechanism;
FIG. 14 is an end elevation along the line 14--14 of FIG. 1 showing
elements of the clamp control mechanism;
FIG. 15 is an end elevation along the line 15--15 of FIG. 2 showing
the manually actuable pilot valves for controlling the clamp
functions;
FIGS. 16, 17, 18 and 19 depict schematically the operating sequence
of the clamp; and
FIGS. 20, 21 and 22 are diagrammatic representations of the
pneumatic control system for the clamp.
In FIG. 1, the internal pipe line-up clamp of the invention,
indicated generally by the reference numeral 10, is shown disposed
in an intermediate position within a first pipe line section
P.sub.1 to which another pipe section P.sub.2 (FIG. 2) is to be
welded in end-to-end relationship. The function of the clamp 10 is
to grip the adjacent ends of pipes P.sub.1 and P.sub.2 and position
and maintain them securely in a precisely aligned and spaced-apart
end-to-end relationship for welding.
The clamp 10 comprises six basic sub-assemblies:
1. The pipe engaging members or clamping shoe sets;
2. the clamping shoe support linkages;
3. the clamping shoe actuation mechanisms;
4. the set-in pipe positioning and back-spacing mechanisms;
5. the clamp drive and conveying mechanisms; and
6. the clamp control mechanisms.
Referring first to FIGS. 1-6, there are two clamping shoe sets 14,
15 each comprising a plurality of peripherally spaced clamping
shoes 16. As best shown in FIGS. 3, 4 and 5, the shoes 16 are
removably secured to mounting blocks 20 by means of tenons 21 and
counter-sunk screws shown, for example, at 23 in FIG. 5. Peripheral
spaces 24 are provided between the adjacent shoes 16 in each clamp
set 14, 15 to permit their radial movement in operation. By the use
of removable shoes, shoes with different radial thicknesses may be
selectively used to adapt the clamp for use with pipe sections of
different diameters. Shoes 16 may also be provided with different
types of facings such as hard rubber, low friction plastics etc.
Also, according to the invention, the shoes 16 may have different
peripheral configurations to adapt them for use with thick wall or
thin wall pipes. For thick wall pipes, as shown in FIG. 7, shoes 16
are formed with forward portion 17 of greater radial thickness than
the rearward portion 18 so that when the shoes are moved into
engagement with pipe sections P.sub.1, P.sub.2, the forward
portions 17 contact the pipe surface first. For use with thin wall
pipe sections, as shown in FIG. 8, shoes 16 preferably are formed
with slightly curved rearward portion 19 which has a radial
diameter slightly greater than that of the forward portion 19':
this enables imposition of the main clamping pressure at a point
back from the pipe end thereby ensuring that the pipe can be firmly
clamped without over-stressing it at its outer end.
Each of clamping shoe mounting blocks 20 is formed with a tandem
clevis 30 on its radially inwardly disposed side. The clevises 30
are pivotally connected by means of transverse pins 31 with the
radially outer ends of tandem link pairs 32. Blocks 20 are also
pivotally connected to generally axially and outwardly directed
link arms 34, the other ends of which are pivotally connected as
indicated at 38 to the radially outer end of fixed radial brackets
40 in the case of shoe set 14 and as indicated at 39 to the outer
end of fixed radial bracket 41 in the case of shoe set 15. Brackets
40, 41 are secured to the actuator housings of the clamp. In
operation, the link arms 34 permit radial movement of shoe sets 14,
15 but limit axial movement thereof with respect to brackets 40 and
41, respectively. It should be noted, however, that shoe sets 14
and 15 are coaxial but mounted independently of each other so that
in operation, although they are maintained in axial alignment, they
can be moved axially with respect to each other as is explained
later.
The radially inner ends of the link pairs 32 of each shoe set are
pivotally connected by mounting blocks 42 to axially movable piston
rod element, indicated generally 45 for set 14 and at 46 for set
15, so that the link pairs 32 convert axial movement of the piston
rod elements 45, 46 into radial movement of the clamping shoe sets
14 and 15 respectively.
Each link pair 32 is comprised of first link members 43 and second
link members 44 pivotally mounted between shoe support blocks 20
and piston rod mounting blocks 42 in a tandem arrangement. Link
pairs 32 are constructed with a limited arc pivot joint at their
mid-points which permits them to be selectively positioned in an
"extended" or operative position as shown in FIG. 3 or in a
"retracted" or non-operative position as shown in FIG. 4. This
retractility of the link pairs 32 ensures ample clearance between
the clamping shoe sets 14, 15 when the clamp is traversing a pipe
section, particularly a curved pipe section, after a weld is
completed and the clamp is being moved to a new joint. The
structural details of each link pairs 32 can be seen by reference
to FIG. 6. FIG. 6 shows the construction of one link pair 32
associated with shoe set 15, but it will be appreciated that each
of the link pairs 32 (eight for each clamp shoe set in the
embodiment illustrated) have an identical construction and that the
link pairs associated with shoe set 14 are merely reversed with
respect to their axial disposition. Link pairs 32 include tandem
links 43, 44 each of which is formed of two half-links 50, 50' and
51, 51'. The inwardly disposed ends of the half-links 50, 50' and
51, 51' are formed with arcuate saddle portions as indicated at 49,
49' adapted to seat on central pins 54. Pins 54 are provided with
two holes as shown at 55 through their diameters adapted to receive
bolts such as 56 in counterbored relationship. Threaded holes 57
corresponding to holes 55 are provided in half link portions 50',
51' to receive bolts 56. The arcuate saddle elements 49, 49' each
is comprised of segments of less than 180.degree. so that there is
an open segment, as indicated at 60 in FIGS. 3 and 4, in the pivot
joint between each half link which permits limited pivotal movement
of the half links from the extended of "in line" position as shown
in FIG. 4. Half-links 50, 51 are secured together for limited
pivotal movement by means of spacer rings 62 which circumscribe
pins 54 and are attached to half links 50, 51 by means of screws
such as shown at 63 threaded into holes 64. Links 44, 43 are
connected at their central pivot joints by means of link element 65
which, in turn, is secured to pins 54 by means of retainer ring 66
and co-operating grooves 67 formed in pins 54. It can be noted that
central pivot joints are arranged such that the link pairs 32
associated with each shoe set can pivot from the extended position
to the retracted position only to the left in the case of link
pairs associated with clamp shoe set 14 and, in the case of link
pairs associated with shoe set 15, as shown in FIGS. 3 and 4 only
to the right.
In their normal pipe traversing disposition, link pairs 32 are in a
retracted condition as shown in FIG. 4 to provide maximum clearance
between clamping shoe sets 14, 15 and the inner circumference of
the pipe section through which the clamp 10 is moved preparatory to
positioning between pipe joints P.sub.1, P.sub.2 for clamping the
pipe ends for welding. Means are provided, therefore, for effecting
movement of the link pairs 32 from their retracted position to
their extended position. This means includes lever arms 70 fixed at
a slight angular disposition to the radially inward ends of links
44. The other ends of levers 70 are provided with saddle elements
72 which are pivotally connected by means of pins 74, 75 to annular
axially movable spider members 76 (see FIG. 5) and 77 which, in
turn, are fixed to annular piston rod elements 78, 79 which are
adapted for axial reciprocatory movement along cylindrical central
rod 80.
Piston rod elements 78, 79 are fixed to annular pistons 81, 82
respectively which are positioned for axial reciprocal movement
within annular cylinders 83, 84. Suitable piston rod sealing rings
85 and piston sealing rings 86, are provided to ensure a pressure
tight seal between the relatively movable elements. Compression
springs 90, 91 between the piston and cylinder end walls bias
pistons 81, 82 to the right and left respectively thereby providing
a spring assist for the movement of pistons 81, 82 and associated
pivot links to the "straight" or extended position, as shown in
FIG. 3. Pressurization of cylinders 83, 84 through conduits 92, 93
respectively will move pistons 81, 82 towards the right and left
respectively with accompanying extension of link pairs 32, as shown
in FIG. 3, with assist springs 90, 91 ensuring that this action
will take place with relatively low pressure.
As noted above, axial movement of annular piston rod elements 45
and 46 effects radial movement of shoe sets 14, 15 respectively
through the medium of the link pairs 32. According to the
invention, axial movement of piston rod elements 45, 46 is effected
by means of a dual actuator arrangement associated with each shoe
set 14 and 15. This permits imposition of staged and large clamping
pressures on the inner circumference of the pipe sections P.sub.1,
P.sub.2. For the purposes of this description, the four clamp shoe
actuators are referred to herein from time to time as actuators A,
B, C and D. Actuators A and B are operatively associated with shoe
set 14 and actuators C and D with shoe set 15. Referring
particularly to FIGS. 3 and 4, actuator A is indicated generally by
numeral 100, actuator B by numeral 102, actuator C by numeral 104
and actuator D by numeral 106.
The structure and operation of actuators 104 and 106 (C and D) will
be described first. Actuator D includes an annular cylinder 110
defined by housing comprising a first casing member 111 and a
second casing member 112 secured together, such as by bolts (not
shown) through inset peripheral flanges indicated at 113, 114.
Positioned for axial movement within cylinder 110 is an annular
piston member 115 in the form of a radially disposed plate
peripherally secured in a pressure-tight manner by resilient
diaphragm 116 clamped between flanges 113 and 114. The radially
inner end of piston 115 is integral with sleeve member 117 which is
axially movable with respect to casing members 111 and 112 and
which functions as a piston rod for piston 115. Suitable
pressure-tight seals 118 are provided between sleeve member 117 and
casing members 111 and 112 to prevent air loss when cylinder 110 is
pressurized.
Actuator 104 (C) includes annular casing member 120 which is
integral with casing member 112 and has an inset peripheral flange
121. A second piston 122 in the form of a radially extending
annular plate is peripherally secured in a pressure-tight
relationship to flange 121 by means of a resilient diaphragm 123
clamped to the flange 121 with ring flange 124. The inner radial
end of piston 122 is integral with sleeve 117 and also is fixed to
piston rod element 46. An air-tight annular chamber 125 is defined
between wall casing means 120 and piston 122.
In operation, the introduction of air under pressure into cylinder
110 on the right side of piston 115 will cause piston 115 to move
axially to the left as viewed in FIGS. 3 and 4 and this movement
will be transmitted by sleeve 117 and piston rod element 46 to link
pairs 32 to cause, in turn, the clamping shoe set 15 to move into
engagement with the inner circumference of pipe section P.sub.1.
Also, application of pneumatic pressure to chamber 125 will cause
piston 122 to move axially to the left. This serves to increase the
force exerted on line pairs 32 and shoe set 15 by virtue of the
increasing of the piston area acted on by air pressure. The force
resulting from the pneumatic pressure on piston 122 is transmitted
through sleeve 117 and piston rod element 46, which are common to
both piston 122 and piston 115.
The structure and function of actuators 100 and 102 (A and B) and
the mechanism for transmitting the axial movement of these
actuators to clamp shoe set 14 for clamping pipe section P.sub.2 is
essentially the same as that just described for actuators 104, 106
(C and D) of clamp shoe set 15. The mechanisms are, of course,
reversed with respect to their axial dispositions. In addition, it
should be noted that for purposes which are explained later, the
housing of actuators 100 and 102 is fixed to central rod 80 by
means of end cover plate 134 which is secured to the end of rod 80
and to portion 131' of actuator casing member 111', whereas the
housing of actuator 104 and 106 is not fixed to rod 80.
The set-in pipe positioning and back-spacing mechanisms of clamp 10
will now be described. In general, according to the invention, this
mechanism is provided for the purpose of first clamping and drawing
the set-in pipe section P.sub.2 into precise end-to-end abutting
relationship with the previously welded pipe section P.sub.1 and
then back-spacing the set-in pipe P.sub.2 a predetermined distance
while retaining the two sets of clamping shoes 14, 15 and the ends
of pipes P.sub.1 and P.sub.2 in precise axial alignment. Referring
particularly to FIGS. 9, 10, 11 and 12, means are provided for
retaining the clamp shoe sets 14, 15 in axial alignment which
include a plurality of axially extending rods 150, 151 arranged
around and interconnecting the peripheral flanges 121, 124 of
actuator 104 with peripheral flanges 121', 124' of actuator 102. As
shown in FIG. 10, rods 150 are of cylindrical configuration and
have one end fixed in perpendicular relationship to the flange 124'
of actuator 102 by means of welding, as shown at 160, and bolted
bracket 161. The other end of rod 150 has a reduced cylindrical
portion 162 which is slidably fitted in a cylindrical bearing
member 163 which is secured to the peripheral flange of actuator
104 by a suitable means such as bolts 164.
As shown in detail in FIG. 11, rods 151 also have one end fixed to
peripheral flange 124' of actuator 102 by means of welding at 170
and bolted bracket 171. However, the other end of rods 151 passes
through the peripheral flanges 121, 124 of actuator 104 and
projects on through the peripheral flanges 114, 113 of actuator 106
as well. Rod 151 has a first reduced-size portion 172 which is
slidably received in a bearing member 173 fixed to peripheral
flange 124 by means of bracket 174 and bolts 175.
A stop block 200 is rotatably mounted on a second reduced portion
of each shaft 151 between flanges 121 and 114. Stop block 200,
together with other elements described later, functions to effect
accurate back-spacing of the clamped set-in pipe P.sub.1 a
predetermined distance from the clamped welded pipe P.sub.2 after
the pipe ends have been brought into precise alignment and abutting
relationship. The stop block 200 includes a body portion 201 and a
pair of axially extending studs 202, 203 threaded therethrough.
Block 200 is held in an axially fixed position on rod 151 by means
of a shoulder 210 on shaft 151, spacer 211, a pair of thrust
washers 212 and 212' and a lock nut 213, threaded on the rod and
abutting a second shoulder 214. A suitable low friction bushing 177
is provided in the peripheral flanges 114, 113 of actuator 106 to
slidably receive the outer end portion 176 of rod 151.
Rigidly secured to each block 200 is a pivot arm 220 which is
pivotally connected by pin 221 to piston rod 222 of a pneumatic
actuator 223 (actuator F). Actuators 223 are pivotally secured to
anchor blocks 224 fixed to casing member wall 120 of actuator 104.
Two blocks 224 serve to anchor the ends of the four actuators 223
as shown in FIG. 9.
Actuators 223 function to selectively rotate blocks 200 from the
position shown in FIG. 11 with studs 202, 203 in axial alignment
with bolt heads 225, 226 to the position shown in FIG. 12 in which
the studs 202, 203 are not aligned with bolt heads 225, 226. As is
described later, rotation of blocks 200 from the latter,
non-aligned position to the aligned position enables back-spacing
of the set-in pipe P.sub.2 a predetermined distance from the end of
welded pipe section P.sub.1 to provide a precise,
controlled-dimension gap between the adjacent pipe ends which
facilitate welding.
From the foregoing description, it can be seen that the sets of
shoes 14, 15 and associated actuators A, B and C, D, respectively,
are retained in axial alignment by rods 151 and 150 but are adapted
for axial displacement with respect to each other without loss of
axial alignment. Axial displacement of the clamp shoe sets and
associated actuators with respect to each other is effected by
means of actuator mechanism 250 (actuator E). As shown in FIGS. 3
& 4, actuator 250 consists of an annular cylinder 251 defined
by an annular inner end wall 252 which is integral with casing wall
111 of actuator 106 and an outer wall 253 which is secured by means
of flange 254 to flange 255 of inner wall 252. A piston member 256
which is in the form of an annular, radially extending plate, is
positioned in cylinder 252 for axial movement. Piston 256 is
peripherally secured in a pressure-tight manner by resilient
diaphragm 258 which is also clamped between casing flanges 254,255.
The radially inner end of piston 256 is fixed to central rod 80
such that the rod 80 functions as a piston rod for piston 256.
Selective introduction of pneumatic pressure to cylinder 251 will
axially displace central member 80 either to the left or right in
FIG. 4. Since member 80 is fixed to casing end cover 134 which is
fixed to the casing of actuators 100 and 102, axial movement of
member 80 will axially displace clamp shoe set 14 and its
associated actuators 100 and 102 with respect to clamp shoe set 15
and its associated actuators 104 and 106.
Referring again to FIG. 11, it can be seen that axial movement of
rods 151 to the left in FIG. 12 will be limited by the engagement
of studs 202, 203 with bolt heads 225, 226. Thus, the amount of
back-displacement of clamp shoe set 14 with respect to clamp shoe
set 15 and the amount of back-spacing of set-in pipe section
P.sub.2 from pipe section P.sub.1 can be selectively varied by
adjustment of studs 202, 203 in stop blocks 200.
The clamp 10 of the invention includes means for conveying the unit
through pipe sections and for automatically positioning the clamp
at the forward end of the welded pipe line for receiving and
clamping a new pipe section. As can be seen in FIGS. 1 and 2, a
plurality of rollers 300 are mounted on the housings of actuators
100 and 106 by means of mounting clevises 301 and brackets 302.
Mounted on the casing of rear actuator 106 by means of radial
bracket 305 is a drive wheel 310 having a rubber tread traction
surface and being adapted to engage the interior of the pipe wall
beneath the clamp unit in the central region of the pipe
section.
Drive wheel 310 is operatively connected with a conventional,
instantly reversible air driven motor 311. The motor control
mechanism 320 is shown in FIG. 13 and comprises an axially aligned
cam 321 mounted on a rod 322 mounted for slidable radial movement
in a fixed sleeve 323. A helical compression spring 324 is disposed
in sleeve 323 around the upper end 325 of rod 322 such as to
normally urge the rod and its cam 321 radially outwardly. A fixed
stop 326 and a co-operating keyway 327 in the upper section of rod
322 serve to restrict the extent of radial movement of rod 322.
The cam 321 is provided with a rearwardly directed and radially
extending cam face 328 which is provided for end abutment with the
end surface of the welded pipe line section P.sub.1 and with a
forwardly directed oblique cam surface 329 for engagement with the
leading edge of the set-in pipeline section P.sub.2 so that, during
the positioning of pipe section P.sub.2 about the clamp shoe set
14, the cam 321 will be urged radially inwardly. The purpose of the
notch 330 adjacent cam surface 328 will become apparent when the
description of the operation of the line-up clamp is given.
Diametrically opposite the keyway 327, the rod 322 is provided with
a cam surface 331 which co-operates with a spring return cam
actuated pilot valve 332 for the purpose which will become apparent
as the description proceeds.
The sleeve 323 is mounted on a shaft 333 which has opposed
reduced-size cylindrical portions 334, 334' slidably fitted for
limited axial movement in bushed housings 335 and 335'. Housings
335 and 335' are fixed to the peripheral flanges 124' and 124 of
actuators 102 and 104, respectively. A helical compression spring
336 is disposed within housing 335 between the end of shaft portion
334 and the face of flange 124' so that shaft 333 is constantly
biased to the right as viewed in FIG. 13. A stud 337 is axially
threaded into shaft end portion 334 and projects through an opening
in flanges 124', 121' with sufficient clearance to permit free
axial movement. Lock nut 338 is provided to adjust and limit axial
movement to the right of stud and attached shaft 333. A stud 340 is
axially threaded into reduced portion 334' of shaft 333 and
projects through an opening in flanges 124 and 121 of actuator 104
with sufficient clearance to permit free axial movement thereof.
Stud 340 terminates in a cam member 341 which is operatively
associated with spring return, cam operated pilot valve 343 mounted
on a bracket 344 secured between the casing walls of actuators 104
and 106. Axial movement of stud 340 is limited by lock nuts
342.
As shown particularly in FIGS. 1, 2, 14 and 15, the clamp handle
and control mechanisms comprise a protective frame consisting of
tubular frame members 350 fixed to circular frame member 351 which,
in turn, is attached by brackets (not shown) to the peripheral
flange 113' of actuator 100. Frame elements 350 extend radially
forwardly and inwardly and are fixed to a central flange 352
positioned coaxially with central rod 80 of the clamp. Mounted in
flange 352 is a bearing member 353 which rotatably supports a stub
shaft 354. The inner end of stub shaft 354 projects through bearing
353 and has a crank element 355 mounted thereon in operative
relationship with spring return, cam operated pilot valves 416,
441, 451, 454, 475 and 477 which are mounted on a control valve
support assembly 357 and which control the flow of pneumatic
pressure to the various clamp actuators as will be explained later.
As shown particularly in FIGS. 2 and 15, assembly 357 includes
annular mounting ring 380 fixed co-axially with respect to shaft
354 by means of axially extending support rods 381 secured to cover
plate 134. A bracing element 382 is fixed to rods 381 about midway
between ring 380 and plate 134. A connecting rod 356 of a length at
least equal to the length of the longest pipe section to be welded
is removably connected to stub shaft 354 by means of a first
coupler 358. Rod 356 is connected by a second coupler 359 to an
outer stub shaft 360 which is journalled for rotation within frame
361.
A control handle 363 is fixed to shaft 360 to permit shaft 360 and
the connecting rod 356 to be selectively rotated thereby turning
stub shaft 354 and associated crank means 355 to actuate the cam
operated pilot valves 416, 441 451, 454, 475 and 477. A pointer 364
is also attached to stub shaft 360 to visually indicate, in
conjunction with dial 362, the clamp function which is effected at
each position of the control handle. A frame 370 and protective end
cover 371 are provided to prevent damage to or accidental actuation
of the control mechanisms. The circumferentially spaced support
rollers 372 are secured around frame 361 to center the control head
in pipe section P.sub.2.
Referring now to FIGS. 20, 21 and 22, the pneumatic control circuit
for clamp 10 includes a two-compartment compressed air supply tank
400 which, as shown in FIGS. 1 and 2 for example, is secured by
mounting brackets 401 to the casing wall of actuator 250. A high
pressure compartment 402 of tank 400 is connected via conduit 403
through air applied, spring return four-way valve 404 (FIG. 22) and
conduit 398 to reverse drive inlet port 397 of drive motor 311.
The low pressure compartment 405 of tank 400 is provided with a
safety valve 406 and is connected via conduit 407 through
non-return valve 408 with conduit 403. Valve 408 permits flow of
air from tank compartment 405 to compartment 402 when the pressure
in the latter compartment drops below that of 405.
Low pressure compartment 405 is also connected via conduits 409 and
main pressure supply line 410 with the forward drive inlet port 412
of drive motor 311 through the circuit shown in FIG. 22. This
circuit includes single air operated spring return three-way valve
413 connected by conduit 414 to spring return pilot valve 343 (see
also FIG. 13) which, in turn, is connected with the main low
pressure air supply line 410. The outlet side of valve 413 is
connected through manually operated spring return, pilot valve 416,
conduit 417, valve 404 and conduit 418 with the drive motor forward
drive inlet port 412. Automatic control pilot valve 332 (see also
FIG. 13) is connected via conduit 419 to conduit 417 and via
conduit 420 to valve 404 so that actuation of pilot valve 332
actuates valve 404 to shut off the air to conduit 418 and to admit
high pressure air through conduit 398 and port 397 to instantly
reverse the motor 311.
The pneumatic control circuit for actuators A, B, C, D, E, and F
includes main air supply conduit 440 connecting low pressure tank
compartment 405 with the actuator cylinders through the circuit
shown in FIG. 21. Referring first to actuator B, main air supply
line 440 is connected through manually operated pilot valve 441,
conduit 442, double air operated four-way valve 443 and conduit 444
with cylinder 135' of actuator B. Valve 443 is also connected via
conduit 445 with conduit 450. Conduit 450 is connected to air
supply line 440 through cam operated pilot valve 451 and is
connected with the right side of cylinder 110' of actuator A
through air supply spring return four-way valve 452 and conduit
453. Valve 452 is also connected to cam operated pilot valve 454
through conduit 456. Valve 452 is connected by conduit 455 to the
left side of cylinder 110' of actuator A. Valve 443 is also
connected through conduit 457 with the right side of cylinder 83
(see also FIG. 3) of actuator G'. The left side of cylinder 83 is
connected via conduit 92 with cylinder 125'.
Cylinder 125 of actuator C is connected via conduit 460 with single
air operated spring return four-way valve 461 and to manually
operated air return three-way valve 462. Valve 462 is also
connected to conduit 450 via conduit 463. Valve 461 is connected
through conduit 364 with the right side and through conduit 365
with the left side of cylinder 110 of actuator D. Conduit 365 also
is connected through conduit 366 with the left side of cylinder 84
of actuator G. The right side of cylinder 84 is connected via
conduit 93 with cylinder 125.
Conduite 470 and 471 connect the right and left sides respectively
of cylinder 251 of actuator E with double air operated four-way
valve 472. Valve 472 is connected through conduit 474 with manual
cam operated pilot valve 475 and is also connected via conduit 476
to manual cam operated valve 477 which, in turn, is connected with
air supply line 440. Switch 477 is connected to the extend and
retract sides of actuator F via conduits 483 and 484 respectively.
Finally, valve 480 is also connected to air supply line 440 through
conduit 450 and switch 451.
For purposes of explaining the operation of the clamp, it will be
assumed that welding of two adjacent pipes has been completed, the
clamping pressure has been released and the clamp 10 is ready to be
moved to the forward end of the pipe line for clamping a new set-in
pipe joint P.sub.2 for welding to the previously welded pipe
section P.sub.1. At this point, the pipe clamping shoe sets 14 and
15 will be in a fully retracted position as shown structurally in
FIG. 4 and schematically in FIG. 16. The clamp backstop mechanism
320 will be in the retracted position with the cam member 321
abutting the inner surface of the pipe section P.sub.1 also as
schematically illustrated in FIG. 16. To initiate operation of the
pipe clamp from this point, motor 311 is actuated by turning
control handle 363 to actuate pilot valve 416 admitting air through
valve 404 to the forward drive inlet 412 of motor 311 thereby
driving the clamp forward. When the clamp 10 reaches the front end
of pipe section P.sub.1, cam 321 and rod 323 move radially
outwardly under the action of spring 324 to the position shown
schematically in FIG. 17. This movement actuates pilot valve 332
which admits air through conduit 420 to valve 404 closing conduit
418 and opening conduit 398 to admit high pressure air to motor 311
through reverse drive inlet port 397. The reverse drive of motor
311 continues until surface 328 of cam 321 is forced into
engagement with the end of pipe section P.sub.1 as shown in FIG.
18. This causes shaft 333 carrying cam member 341 to be pushed to
the left against the bias of spring 336 (FIG. 13). This, in turn,
causes actuation of pilot valve 343, also as shown in FIG. 18,
which admits air to valve 413 to shut off the high pressure,
reverse drive air supply and stop the motor 311.
Valve 462 is then opened, either manually or by pilot valve means
which is automatically actuated when the reverse drive air supply
is cut off. This admits air to cylinder 125 of actuator C and to
the right side of cylinder 110 of actuator D. Pressurization of
cylinder 125 also admits air pressure to cylinder 84 via conduit 93
(see FIG. 3). This causes piston 82 of actuator G to move to the
left, as viewed in FIGS. 3 and 4, straightening link pairs 32 to
their extended or operative positions, as shown in FIG. 3. This
straightening action occurs before sufficient pressure is built up
in cylinder 125 to cause axial movement of piston 122 because the
assistance provided by spring 91 and also because much less
pressure is required to actuate piston 82 in cylinder 84 than is
required to move piston 122 of actuator C. After links 32 are
extended, pressure buildup in actuators C and D continues and
causes pistons 115 and 112 to move to the left forcing clamp shoe
set 15 into engagement with pipe section P.sub.1.
The set-in pipe section P.sub.2 is then introduced over projecting
clamp shoe set 14 as shown in FIG. 18, and actuator B is activated
by pilot valve 441 which opens valve 443 to admit air through
conduit 444 to cylinder 125'. This results first in the
straightening of link pairs 32 by actuation of piston 81 of
actuator G' in a similar manner to that just described for link
pairs 32 and piston 82 and, second, in the engagement of clamp shoe
set 14 against pipe P.sub.2 as shown in FIG. 18. At this point,
actuator A has not yet been pressurized and pipes P.sub.1 and
P.sub.2 are not necessarily in alignment. Actuator E is next
pressurized by actuation of pilot valve 475 which opens valve 472
to admit air through conduit 471 to the left side of cylinder 251.
This causes piston 256 to move to the right pulling clamp shoe set
14 and clamp set-in pipe section P.sub.2 into end abutting
relationship with pipe section P.sub.1. Pilot valve 454 is then
activated to open valve 452 to pressurize the left side of piston
115' of actuator A thereby forcing piston 115' to the right,
increasing the pressure of clamp shoe set 14 to round out the end
of pipe P.sub.2 and ensure true axial alignment with the end of
pipe P.sub.1.
Next, actuator F is pressurized by an activation of pilot valve 477
which opens valve 480 to cause piston rod 222 to extend. This
results in rotation of stop blocks 200 such that studs 202, 203 are
in axial alignment with bolt heads 225, 226 as shown in FIG. 11.
Actuation of pilot valve 477 simultaneously opens valve 472 to
effect pressurization of the right side of cylinder 251 of actuator
E thereby causing piston 256 to move to the left until studs 202,
203 come into engagement with bolt heads 225, 226 as shown in FIG.
11. By selective adjustment of studs 202, 203, pipe section P.sub.2
will be spaced back from pipe section P.sub.1 as shown in FIG. 19,
a distance which provides an optimum gap for welding having regard
to the pipe diameters, type of welding system employed, etc. Also,
as shown in FIG. 19 and FIG. 2, with the clamp 10 in this position
cam 321 is disposed with notch 330 adjacent the gap between the
pipes P.sub.1 and P.sub.2 so that cam 321 will not interfere with
the welding operation.
The welding operation is then carried out. At completion of the
welding operation, pilot valve 451 is activated and actuators A, D,
G' and G are pressurized so as to cause pistons 115, 82 and 115',
81 to move to the left and right respectively thereby retracting
the clamp shoe sets 14 and 15. At the same time, cylinders 125' and
125 are vented to the atmosphere and piston rod 222 of actuator F
is retracted to rotate the stop blocks 200 to the non-aligned
position shown in FIG. 12. Also, cylinder 251 is pressurized via
conduit 470 to fully extend piston 256 to the left.
The line-up clamp of the invention has numerous important
advantages over the clamps heretofore known and used in the
pipeline construction industry. Foremost of these advantages is the
adaptability of the clamp for use with automatic pipe welding
systems. In order to function effectively, automatic welding
requires extremely accurate alignment of the adjacent pipe ends as
well as a uniform gap between the opposed surfaces which are to be
joined. Heretofore, in order to obtain the necessary uniformity of
alignment and spacing, it has been necessary to first clamp the
pipes then cut or grind the ends to provide the desired gap. This
expensive and time-consuming procedure can be eliminated through
use of the clamp of the present invention.
* * * * *