U.S. patent application number 12/380580 was filed with the patent office on 2009-12-31 for tube making machine with diameter control and method.
Invention is credited to William James Kephart.
Application Number | 20090320542 12/380580 |
Document ID | / |
Family ID | 41445846 |
Filed Date | 2009-12-31 |
United States Patent
Application |
20090320542 |
Kind Code |
A1 |
Kephart; William James |
December 31, 2009 |
Tube making machine with diameter control and method
Abstract
A spiral pipe forming system and method which include automatic
diameter or dimension sensing and correction.
Inventors: |
Kephart; William James;
(Brentwood, CA) |
Correspondence
Address: |
Philip A. Dalton
236 West Portal Ave., #15
San Francisco
CA
94127-1423
US
|
Family ID: |
41445846 |
Appl. No.: |
12/380580 |
Filed: |
February 26, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12321370 |
Jan 16, 2009 |
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12380580 |
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61011677 |
Jan 18, 2008 |
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Current U.S.
Class: |
72/49 |
Current CPC
Class: |
B21C 37/121
20130101 |
Class at
Publication: |
72/49 |
International
Class: |
B21C 37/12 20060101
B21C037/12 |
Claims
1. Apparatus for forming a spiral pipe, comprising lead, mandrel
and buttress rolls for forming a spirally wound sheet, the
apparatus further including inner and outer pressure rolls engaging
and crimping together adjacent edges of the spirally wound sheet; a
sensing system for monitoring changes in the diameter of the
spirally wound sheet as it is formed and responsively generating
signals containing information regarding changes in diameter; and a
system responsive to the signals, for moving the buttress rolls
toward or away from the mandrel rolls and the pressure rolls to
thereby correct the changes in diameter.
2. Apparatus for forming a spiral pipe, comprising lead, mandrel
and buttress rolls for forming a spirally wound sheet, the
apparatus further including inner and outer pressure rolls engaging
and crimping together adjacent edges of the spirally wound sheet; a
sensing system for monitoring changes in the diameter of the
spirally wound sheet as it is formed and responsively generating
signals containing information regarding changes in diameter; a
system responsive to the signals indicating relatively small
changes in pipe diameter, for moving the inner and outer pressure
rolls in unison radially inward or outward relative to the axis of
the pipe, to correct the relatively small changes in diameter; and
a system responsive to the signals indicating relatively large
changes in pipe diameter, for moving the buttress rolls toward or
away from the mandrel rolls and the pressure rolls, to correct the
relatively large changes in diameter.
3. A method of forming a spiral pipe with diameter control,
comprising: using lead, mandrel and buttress rolls, forming a
spirally wound sheet having adjacent edges; using interior and
exterior pressure rolls, crimping adjacent edges of the sheet
together; monitoring the diameter of the spirally wound sheet for
changes therein; responsive to changes in the diameter, generating
signals containing information regarding the changes in diameter;
and automatically applying diameter correction selected from (1)
moving the inner and outer pressure rolls in unison radially inward
or outward relative to the axis of the spirally wound sheet, to
move the adjacent edges of the spirally wound sheet together, to
thereby correct relatively small changes in diameter; and (2)
moving the buttress rolls toward or away from the mandrel rolls and
the pressure rolls, to thereby correct relatively large changes in
diameter.
Description
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 12/321,370, titled "Tube Making Machine with
Diameter Control and Method," filed Jan. 16, 2009, inventor William
J. Kephart, which parent application claims the benefit of U.S.
provisional application No. 61/011677, titled "Tube Making Machine
with Diameter Control and Method," filed Jan. 18, 2008, inventor
William J. Kephart. Both prior applications are hereby incorporated
by reference.
BACKGROUND OF THE INVENTION
[0002] A. Field of the Invention
[0003] The present invention relates to machines and methods for
making spiral pipe from strips of sheet metal and, in particular,
to machines and methods for accurately monitoring and controlling
the diameter of such pipe. As used here, "pipe," tube" and
"conduit" are used interchangeably.
[0004] B. Description of the Related Art
[0005] Commonly assigned U.S. Pat. No. 3,940,962 describes a
three-roll conduit forming mill and diameter control of Pacific
Roller Die Company, Inc. The '962 patent is incorporated by
reference in its entirety. As described in the '962 patent, the
adjacent spiral edges of a strip which forms a spiral conduit are
joined by interlocked edge flanges which are pinched or crimped
tightly together by upper and lower lock-up rolls. The radial
positioning of this pair of rolls relative to the conduit axis
controls the diameter of the conduit. Thus, when the rolls are
simultaneously raised, i.e., moved radially inward relative to the
axis of the conduit, the diameter of the conduit increases When the
rolls are simultaneously lowered, i.e., moved radially outward
relative to the conduit axis, the diameter of the conduit
decreases. The position of the lock-up rolls is changed by control
screws which are manually turned using wrenches. The '962 patent
indicates the diameter changes effected by such movement are minor
and occur gradually. For instance, in a machine for making 1 to 36
inch conduit, such adjustments may be used to effect diameter
changes of approximately.+-.1/4 (one-fourth) inch.
[0006] The '962 patent also discloses the feasibility of making the
adjustment automatic, by including means for monitoring the
diameter, such as a belt or loop detector, which, when it senses a
given diameter deviation would activate a servomechanism which in
turn lowered or raised the lock rolls to correct the deviation.
SUMMARY OF THE INVENTION
[0007] In one aspect, the present invention is embodied in
apparatus for forming a spiral pipe, comprising: lead, mandrel and
buttress rolls for forming a spirally wound sheet, the apparatus
further including inner and outer pressure rolls engaging and
crimping together adjacent edges of the spirally wound sheet; a
sensing system for monitoring changes in the diameter of the
spirally wound sheet as it is formed and responsively generating
signals containing information regarding changes in diameter; and a
system responsive to the signals for moving the buttress rolls
toward or away from the mandrel rolls and the pressure rolls to
thereby correct the changes in diameter.
[0008] In another aspect, the present invention is embodied in
apparatus for forming a spiral pipe, comprising: lead, mandrel and
buttress rolls for forming a spirally wound sheet, the apparatus
further including inner and outer pressure rolls engaging and
crimping together adjacent edges of the spirally wound sheet; a
sensing system for monitoring changes in the diameter of the
spirally wound sheet as it is formed and responsively generating
signals containing information regarding changes in diameter; a
system responsive to the signals indicating relatively small
changes in pipe diameter for moving the inner and outer pressure
rolls in unison radially inward or outward relative to the axis of
the pipe, to correct the relatively small changes in diameter; and
a system responsive to the signals indicating relatively large
changes in pipe diameter for moving the buttress rolls toward or
away from the mandrel rolls and the pressure rolls, to correct the
relatively large changes in diameter.
[0009] In yet another aspect, the present invention is embodied in
a method of forming a spiral pipe with diameter control,
comprising: using lead, mandrel and buttress rolls, forming a
spirally wound sheet having adjacent edges; using interior and
exterior pressure rolls, crimping adjacent edges of the sheet
together; monitoring the diameter of the spirally wound sheet for
changes therein; responsive to changes in the diameter, generating
signals including information regarding changes in diameter; and
automatically applying diameter correction selected from (1) moving
the inner and outer pressure rolls in unison radially inward or
outward relative to the axis of the spirally wound sheet, to move
the adjacent edges of the spirally wound sheet and thereby correct
relatively small changes in diameter; and (2) moving the buttress
rolls toward or away from the mandrel rolls and the pressure rolls,
to thereby correct relatively large changes in diameter.
BRIEF DESCRIPTION OF THE DRAWING
[0010] FIG. 1 is a perspective view of a three roll pipe-forming
mill.
[0011] FIG.2 is an enlarged partial view of the mill of FIG. 1,
depicting an automatic diameter sensing system.
[0012] FIG. 3 is a schematic of an air-operated hydraulic pump
unit.
[0013] FIG. 4 is a schematic depiction of a control system for the
exterior pressure jack and roll.
[0014] FIG. 5 is a partial view of the three-roll pipe forming mill
of the type shown in FIG. 1, depicting a buttress roll control
system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0015] According to an embodiment of the present invention, a three
roll apparatus for forming lock seam spiral pipe of controlled pipe
size or diameter, e.g., constant diameter, includes lead, mandrel
and buttress rolls and seam-forming rolls comprising a
wedge-operated interior pressure roll and jack-operated exterior
pressure roll. The diameter of the spiral pipe and deviations in
the diameter are monitored as the pipe is formed, then responsive
to deviations greater than a predetermined value or values,
different sequences of steps are automatically applied to correct
relatively large and relatively small deviations and, thus,
collectively provide for automatic correction of a relatively wide
range of deviations. Relatively large deviations are corrected by
translating the buttress rolls. Relatively small deviations are
corrected using the seaming dies (pressure rolls), the wedge
position and an associated control system. The control system
pressurizes the exterior pressure roll jack such that a set
pressure can be maintained, As a result, the exterior and interior
pressure rolls can be adjusted up or down by the automatic diameter
control while maintaining full pressure, i.e. without losing full
pressure and causing the lock seam to be unsatisfactory; and wedge
adjustments can be made during production of the pipe without
dumping all pressure and temporarily shutting down the mill, as is
the case with prior systems.
[0016] Responsive to relatively small deviations of 0-10% and
typically 0-5%, the system automatically moves the pressure rolls
up/down, thereby moving the lock seam radially inward/outward, and
increasing/decreasing the diameter of the pipe. Responsive to
relatively large deviations of 2-25% and typically 2-15%, the
system automatically moves the buttress rolls generally
horizontally toward/away from the mandrel and pressure rolls,
thereby decreasing/increasing the diameter of the pipe. Thus, the
system automatically corrects for a relatively wide range of
diameter deviations. The adjustments are incremental so as not to
over adjust and cause the system to oscillate while correcting the
diameter. The small and large corrections can e applied alone or
sequentially.
[0017] FIG. 1 depicts a three-roll pipe forming mill 10 by Pacific
Roller Die Company, Inc which embodies the above system and method.
The system includes a roll former system 12 for feeding a metal
strip 1 to a three roll system 14, which forms the strip into a
helical pipe 3. Diameter sensing and control system 16, FIGS. 2 and
3, monitor the diameter of the formed pipe 3 and responsively
control the diameter of the pipe as it is formed, as indicated by
reference numeral 2.
[0018] As is well known and as described more fully in the commonly
assigned, incorporated patent, U.S. Pat. No. 3,940,962, the roll
former 12 comprises a carriage 22 which is supported by casters 24
so that the oblique angle formed between the roll former and the
three roll system can be varied, to thereby the vary the diameter
of the pipe or tube. The carriage 22 is an elongated frame which
mounts an array 11 of corrugating rolls, arranged in a plurality of
stands of matched pairs of upper and lower rolls. The rolls are
horizontally aligned so that a strip 1 which is input to the roll
former 12 passes through the upper and lower rolls of each stand
and is deformed thereby into a corrugated profile, then exits the
roll former and enters the three roll system 14. Commonly assigned
U.S. Pat. No. 6,339,945 describes a tube-forming system which uses
computer control of the helix angle between the tube infeed system
and the tube forming system, to control and vary tube diameter and
form linearly tapered, curved and constant diameter profiles. U.S.
Pat. No. 6,339,945 is hereby incorporated by reference.
[0019] The operation of the three roll system 14 is also well known
and thus is described in conjunction with the construction and
operation of the diameter (or dimension) sensing and control unit
16 and diameter or dimension sensor or monitor 15 of system 16.
Referring to FIG. 2, the diameter sensing mechanism 15 includes a
support 26 comprising a horizontal base member 28, legs 30 and 32
and a horizontal top member 34. The legs 30 and 32 are bolted to
the floor or other base. A pivot arm 36 is pivotally mounted at one
of a plurality of mounting holes 38 spaced along the lengthwise
dimension of leg 30. A tension spring 42 is pivotally mounted at
one end to the pivot arm 36 and is pivotally mounted at the other
end to bottom leg 28. A wire (or rope or cable, etc.) 40 is mounted
at one end to winch 44, is wrapped one full loop around formed pipe
3, and is attached at the opposite end to the pivot arm 36. Winch
44 and tension spring 42 bias or pull the pivot arm 36 in opposite
directions, such that the winch can be used to orient the pivot arm
in a desired orientation and the tension spring tends to maintain
the pivot arm in the selected orientation. A sensor 46 such as an
ultrasonic sensor is mounted on top member 34 and is focused or
directed onto the pivot arm 36 and provides an output signal
containing information regarding the distance between the sensor
and the pivot arm. During operation of the three roll system 14,
changes in the diameter of the pipe 3 effect movement of the cable
40 and the pivot arm 36, causing variations in the output signal
which are representative of the changes in the diameter, radius,
perimeter or other dimension which is being monitored.
[0020] The diameter or dimension control system 16 for the pipe
forming mill 10 is depicted in FIG. 2 and, in particular, in FIG.
3. The three-roll forming arrangement 14 of Pacific Roller Die
Company includes lead rolls 52, which engage the lower surface of
sheet 1 entering the three roll system 14, mandrel rolls 56 and
interior pressure roll 54 on the upper side of the sheet, i.e., the
interior of the forming pipe 2, and buttress rolls 58 which shape
the sheet helically into the pipe 2. Exterior pressure roll 62
engages the exterior surface of the pipe 2 opposite the interior
pressure roll 54 and the two rolls cooperatively crimp the mating
adjacent edges of the spirally formed sheet together and join the
pipe along the adjacent sheet edges in a seam, or more precisely in
the case of joined hook-shaped edges, in a lock seam.
[0021] The internal pressure roll 54 and the external pressure roll
62 are mounted to positioning devices which cooperatively move the
internal pressure roll and the external pressure roll radially
inward and outward together relative to the axis of the pipe for
effecting the crimping action.
[0022] The positioning device for the internal pressure roll 54
comprises a wedge 64 and mandrel 66 arrangement and a hydraulic
cylinder 68. As shown in FIG. 3, the interior pressure roll 54 is
rotatably mounted to the vertical member or upright of a generally
T-shaped support member 55, the upper horizontal (cross) member of
which is slidably mounted on vertical rods (not shown) extending
generally downward from the mandrel 66. During operation, the
hydraulic cylinder 68 moves the shaft thereof bidirectionally, in
opposite directions shown by arrow 74, and the mandrel 66 cams the
wedge 64 along the angled lower surface of the mandrel and causes
the wedge to move radially up or down. The camming action of the
mandrel moves the wedge, the member 55 and the interior pressure
roll 54 roll radially down against the pressure exerted by the
exterior pressure roll 62, see below (or allows the pressure roll
54 to be moved radially up by the pressure exerted by the exterior
pressure roll).
[0023] The external pressure roll 62 is mounted to shaft or piston
76 of hydraulic jack 78. Operation of the pump unit 90 causes the
jack piston 76 to vary the pressure on the exterior pressure roll
62. The pressurized exterior pressure roll 62 maintains pressure
against the interior pressure roll 54. (In the absence of the
interior pressure roll 54, this pressure would move the exterior
pressure roll 62 radially inward (up) or outward (down), as
indicated by the arrow 82.) Thus, when the wedge 64 is extended to
the left in FIG. 3, the camming action between the wedge and the
mandrel 66 moves the wedge and the interior pressure roll 54
radially down against the pressure exerted by the exterior roll 62,
so that the exterior pressure roll moves with and, the position
thereof is defined by, the interior pressure roll. Conversely, when
the wedge 64 is retracted to the right in FIG. 3, the wedge is
cammed upward by the mandrel 66 and the pressure exerted by the
exterior pressure roll 62 forces the interior pressure roll 54 to
move radially upward along with the exterior pressure roll to a
position defined by the wedge and the interior pressure roll.
[0024] The crimped tube edges or seam follow(s) the position
defined by the interior pressure roll 54 during up and down
movement thereof. That is, the synchronized radially inward and
outward movement of the interior pressure roll and the exterior
pressure roll 62 (with the interior pressure roll defining the
position of the tube seam and the exterior pressure roll following
the interior pressure roll) shifts the position of the pipe seam
radially inward and outward in controlled fashion relative to the
pipe axis.
[0025] Referring further to FIG. 3, the output side of sensor 46 is
connected to control box 84, which can be a separate device or part
of the programmable logic device or computer for controlling the
system 10, and which typically is connected to an operator console
(not shown). The control box is connected to a directional control
valve and check valve arrangement 86 and to an air operated
hydraulic pump unit 88. The directional control valve and check
valve 86 is connected to the hydraulic cylinder 68 for providing
electronic control of the hydraulic fluid which operates the
hydraulic cylinder so that the piston thereof is translated
bidirectionally, as discussed above, for camming the wedge 64 along
mandrel 66 and moving the internal pressure roll 54 (and the
exterior pressure roll 62) radially in and out. The air-operated
hydraulic pump unit or system 88 is connected to the external
pressure roll jack 78 for providing electronic signal controlled,
air-operated hydraulic flow to that jack, for moving the piston 76
thereof bidirectionally, as discussed above, and thereby moving the
external pressure roll 62 radially in and out.
[0026] Referring further to FIG. 3 and in particular to FIG. 4,
there is shown a presently preferred embodiment of the air-operated
hydraulic pump unit or system 88 for controlling the operation of
the air-operated hydraulic pump 90 and the exterior pressure roll
jack 78 and thereby the exterior pressure roll 62. The control
system incorporates the aforementioned components and
interconnected components including reservoir 85, electronic
regulators 81 and 83, unloading valve 87, valve 89 and transducer
91, for pressurizing the exterior pressure roll jack such that a
set pressure can be maintained.
[0027] Referring further to FIGS. 3 and 4, in the depicted system
88, factory air power is connected to both electronic pressure
regulators 81 and 83. Electronic regulator 81 is in the air supply
line to the air/oil pump 90 (1:100 ratio) and is also connected to
the reservoir 85. When activated, the air powers the pump 90 and
builds up pressure in the pressure roll jack 78. Electronic
regulator 83 is connected to the pressure unloading valve 87 for
the oil pressure to be released back to the reservoir.
[0028] In operation of system 88, the desired lock-forming pressure
is defined at the operator console associated with control box 84
and the supply regulator 81 allows enough air pressure to
accumulate at the air/oil pump 90 to reach the pressure set point.
Once under full production mode, the control system 84 continuously
monitors the seaming pressure through the pressure transducer 89,
which is connected between the pressure roll jack 78 and the
control box 84. When a pressure deviation of a predetermined value
is sensed by the transducer 91, a signal is sent to control system
84 and the control system 84 responsively pulses a signal to one of
the two electronic pressure regulators 81/83 to adjust the actual
seaming pressure up or down to match the set pressure previously
entered at the main console. When the actual/sensed pressure is
lower than the set point pressure, the control box 84 pulses a
signal to the air supply regulator 81 to increase the pressure to
the set point. For actual/sensed pressure that is higher than the
pressure set point, the control box 84 pulses a signal to the
unloading regulator 83 to decrease the pressure to the set point.
As alluded to above, this system and method of operation
correct.+-. deviations and allows the set pressure to be maintained
(e.g. within plus or minus 10%). As a result, (1) the pressure
rolls 62 and 54 can be adjusted up or down by the automatic
diameter control while maintaining full pressure, i.e. without
losing full pressure and causing the lock seam to be
unsatisfactory; and (2) wedge adjustments can be made during
production without dumping all pressure and temporarily shutting
down the mill, as is the case with prior systems.
[0029] When the size of the pipe 3 changes, pivoting of the pivot
arm 36 in one direction (for example, counterclockwise; see arrow
37, FIG. 3) is associated with decreases in pipe size, whereas
pivoting of the pivot arm in the opposite direction (clockwise) is
associated with increases in pipe size. When the sensor 46 and the
diameter monitoring and control system 16 detect (typically small)
deviations from the desired pipe diameter, the output from the
sensor 46 causes control box 84 to operate the internal and
external pressure roll positioning devices in unison, and
simultaneously move the internal pressure roll 54 and the external
pressure roll 62 inward or outward relative to the pipe axis and
thereby respectively increase or decrease the diameter of the
pipe.
[0030] Referring to FIG. 5, there is shown a partial, elevation
view of the three roll 14 which depicts a system 100 for mounting
and adjusting the position of the buttress rolls 58. The buttress
rolls 58 are mounted on a slide plate 102 which in turn is mounted
to base plate 101 and translated bidirectionally along the base
plate by a motor 103-driven sprocket drive system 105, FIG. 3,
controlled by the control box 84.
[0031] In the illustrated embodiment electric motor 103 and reducer
104 unit 106 is mounted to the base 31 of the three roll 14. Drive
sprocket gear 108 coming off the reducer 104 mounts and drives a
chain loop 109, which is linked to and drives the buttress roll
mounting subsystem. This subsystem comprises the base plate 101,
the sliding plate 102, which is mounted on top of the base plate
and guided in/out horizontally along gibs 111 (also known as
guides, retainers, tracks, etc.). Two threaded rods 112, 113 are
rotatably journaled to threaded holes in the sliding plate or in
adjustment brackets 114 mounted to the sliding plate 102 so that
reversible rotation of the two rods in unison bidirectionally
moves/translates the sliding plate and the buttress rolls 58.
[0032] Matched sprocket gears 116, 117 are mounted on the rods 112,
113 and are connected by a chain loop 118 so that rotation of one
of the rods rotates the other rod equally and pushes or pulls the
sliding plate 102 and buttress rolls 58. As alluded to, the chain
loop 109 coming off the drive sprocket 108 associated with the
electric motor and reducer unit 106 connects the motor 103 to one
of the driven sprockets 116, 117, illustratively, sprocket 116. The
electric motor 103 is connected to and its operation is controlled
by the control box 84. Ultrasonic sensor 47 is mounted on the base
plate 101, connected to the control box 84 and aimed at the sliding
plate 102 to generate signals that are transmitted to the control
box 84, indicating (monitoring) the position of the buttress rolls
58.
[0033] When the sensor 46 and the diameter monitoring and control
system 16 detect (typically large) deviations from the desired tube
diameter, the operation of the electric motor 103 is controlled by
control box 84 to automatically move the buttress rolls 58
toward/away from the mandrel and pressure rolls a predetermined
distance for decreasing/increasing the diameter of the pipe as
required, Prior to the automatic diameter-correction of the
buttress rolls 58 (and optionally, during the correction process),
the sensor 47 sends signals to the control box 84 containing
information regarding the position of the buttress rolls so that
the control box or other system computer can determine whether
there is sufficient travel available to the buttress rolls to
accomplish the desired correction. If the system determines there
is insufficient travel available, it shuts down the mill to permit
the necessary repositioning.
[0034] The present invention has been described in terms of
preferred and other embodiments. The invention, however, is not
limited to the embodiments described and depicted. Adaptation to
other embodiments will be readily done by those of usual skill in
the art, limited only by the claims appended hereto.
* * * * *