Information
-
Patent Grant
-
6425436
-
Patent Number
6,425,436
-
Date Filed
Friday, June 16, 200024 years ago
-
Date Issued
Tuesday, July 30, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Elve; M. Alexandra
- Kerns; Kevin P.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 164 132
- 164 345
- 164 286
- 164 289
- 164 292
- 164 295
- 164 302
- 241 DIG 10
-
International Classifications
-
Abstract
An apparatus and method for extracting a cast iron pipe from a centrifugal casting machine and for also breaking the continuity of an annular sand core used to form the bell end of the pipe. The apparatus has a carrier member on which are mounted extractor carrier jaw assemblies and core continuity breaking members. The extractor jaw assemblies are movable between extended and retracted positions. One end of the carrier member is inserted into the bell end of the pipe while the pipe is in the casting machine. The extractor jaw assemblies are retracted as the carrier member enters the pipe. As the carrier member enters the pipe, the core continuity breaking members plow through parts of the sand core to break the continuity of the sand core. The extractor jaw assemblies are then extended to contact the interior surface of the pipe wall and the apparatus is retracted, pulling the pipe out of the mold in the casting machine. The sand core is broken into pieces and the chunks of the sand core fall out of the pipe. The pipe may then be processed in the normal manner.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the production of metal pipe, and more particularly, to the production of cast iron pipe with bell ends formed using sand cores.
2. Description of the prior art
In the production of objects such as elongate cast metal pipes, centrifugal casting has been commonly used. In such a casting operation, the pipe is cast in a cylindrical mold. Molten metal, such as iron, is fed into the mold through a trough. The trough has a spout at one end which is curved toward the sidewall of the mold. A sand core is inserted into the bell end of the mold to form the inside contour of the pipe bell. The bell end of the pipe's inside contour typically includes one or more annular grooves or depressions defining a gasket seat area to receive a gasket. The mold is rotated and once it is brought up to the appropriate speed, molten metal is poured into the trough. Once the bell end of the pipe has formed, the mold is moved horizontally while rotating. The stream of molten metal discharged from the spout flows tangentially onto the surface of the mold, where it is held in place by centrifugal force. The molten metal forms a homogeneous pipe with a cylindrical bore.
After the pipe has been completely cast, the mold is kept rotating until the pipe has cooled to a desired temperature. The pipe must then be taken from the casting machine and transferred to a heat treating furnace. In some instances, the sand cores are not removed from the cast pipe before annealing; instead, the sand core is allowed to disintegrate at the temperatures in the annealing oven. However, in other types of production, it is desirable to remove the sand core from the bell end of the pipe before the pipe enters the heat treating furnace. This removal of the sand core is particularly important in plants in which the pipe is set vertically and supported on its bell end in the heat treating furnace; remnant pieces of the sand core could cause the pipe to be off-balance in the furnace, and risks toppling of the pipe.
Traditionally, the sand cores have been manually removed. In the manual process, a worker hits the sand core with a hammer to break the core into smaller pieces, and then scrapes out the pieces of the core using a hoe-type of tool. However, this process has required the worker to be in close proximity to the hot pipe, and has been time consuming, adding to the expense of producing cast iron pipe.
SUMMARY OF THE INVENTION
The present invention addresses the problem of removing sand cores from the bell ends of cast metal pipes.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a top plan view of an example of a portion of a pipe manufacturing facility illustrating the pipe casting station, with the parts simplified for clarity;
FIG. 2
is a side elevation of an embodiment of an apparatus for breaking the continuity of an annular sand core, the apparatus shown entering the open bell end of the pipe with the extractor jaws retracted, the pipe and sand core being shown in cross-section, the pipe being within the mold of the centrifugal casting machine;
FIG. 3
is a side elevation of the apparatus of
FIG. 2
, shown with the extractor jaws extended against the inner surface of the pipe to pull the pipe out of the casting mold as the apparatus is withdrawn from the pipe and with part of the sand core broken off by the breaking member of the apparatus;
FIG. 4
is an enlarged view of the end of the pipe and apparatus as shown in
FIG. 2
, with parts removed for clarity;
FIG. 5
is an enlarged view of the end of the pipe and apparatus as shown in
FIG. 3
, with parts removed for clarity;
FIG. 6
is an end view of the apparatus of
FIGS. 2-5
, shown with the extractor jaws extended as in
FIGS. 3 and 5
;
FIG. 7
is a side elevation of an alternative embodiment of a blade and blade holder for a core continuity breaking member;
FIG. 8
is a side elevation of an alternative embodiment of a pancake-breaking element that can be attached to the core continuity breaking member of
FIG. 7
;
FIG. 9
is a side elevation of an alternative embodiment of a core continuity breaking member; and
FIG. 10
is a side elevation of another alternative embodiment of a core continuity breaking member.
DETAILED DESCRIPTION
An example of a portion of a manufacturing facility or plant
10
for manufacturing an elongate cast metal pipe such as ductile iron pipe is shown in FIG.
1
. The illustrated plant
10
includes a casting station
12
for casting the iron pipe
14
. The casting station
12
may include any centrifugal casting machine
16
known in the art. The plant
10
may also include other standard features, such as an annealing or heat-treating station (not shown) downstream from the casting station
12
, where the cast iron pipe is heated and cooled to produce the desired properties in the metal. Commonly, the cast iron pipe will be heat treated to produce ductile iron pipe.
The casting machine includes an outer mold that defines the exterior surface of the cast metal pipe
14
. A sand core is used to define the contour of the interior surface of the pipe
14
at the bell end
15
. An example of an outer mold is shown at
18
in
FIGS. 2-5
. An example of a sand core is shown at
20
in
FIGS. 2-5
. It should be understood that the pipe
14
, mold
18
and sand core
20
are shown for purposes of illustration only, and that the invention is not limited to the size or shape of pipe, mold and sand core shown unless expressly set forth in the claims.
The sand core typically is made from a mixture of sand and a binder, the binder holding the sand in the form of the core. When the sand core comes into contact with the hot metal in the mold, the part of the core in contact with the metal heats, and the binder is vaporized. Heat is transferred throughout the core, continuing to vaporize the binder.
The present invention is expected to be useful in breaking the continuity of sand cores made from a variety of commercially available binders or other additives. The present invention is also expected to have useful application to varieties of commercially available casting machines, such as the illustrated two-stroke centrifugal casting machine as well as other centrifugal casting machines requiring additional strokes, such as four-stroke casting machines.
As shown in
FIGS. 2-5
, the pipe
14
has an inner surface shown at
17
in
FIGS. 4-5
. At the bell end
15
, the inner surface
17
of the pipe has a contour that includes annular grooves or depressions
19
defining a gasket seat area to receive a gasket. These grooves or depressions
19
are cast around complementary outcroppings shown at
21
in
FIGS. 4-5
on the outer surface of the sand core
20
. The pipe
14
has a central longitudinal axis shown at
23
in
FIGS. 2-5
.
To remove the hot cast iron pipe from the mold
18
in the casting machine
16
, an extractor apparatus can be used. An example of an apparatus incorporating the principles of the present invention is illustrated in
FIGS. 1-6
at
22
. The illustrated apparatus
22
is dual function: it provides for extracting the cast pipe from the mold and for breaking the sand core into pieces to facilitate removal of the sand core.
As shown in
FIGS. 1-3
, the combined pipe-extracting and core-breaking apparatus
22
may be mounted to move longitudinally on a base
25
along spaced rails
24
,
26
toward and away from the casting machine
16
. The combined apparatus
22
may be connected to be driven by any suitable drive mechanism, such as the drive shown schematically at
28
in
FIGS. 1-3
. The base
25
of the apparatus may be mounted on wheels
30
supported on the rails
24
,
26
, and may have stabilizing rollers
32
.
A suitable drive mechanism
28
may be, for example a hydraulic or electric motor with a drive chain connected to the base
25
, and traveling around sprockets (not shown). Alternatively, a hydraulic cylinder may be used to move the apparatus longitudinally. A suitable hydraulic motor is commercially available from Kawasaki Motors Corp., Precision Machinery Division, of Grand Rapids, Mich., Model HMB270 (No. HMB270/P1/S04/30). However, the invention is not limited to use of a drive mechanism, to a hydraulic drive mechanism, to this particular hydraulic drive mechanism or to one having these characteristics unless expressly set called for in the claims. For example, the apparatus
22
could be manually moved. As discussed below, the apparatus could also be stationary, with the pipe and mold in the casting machine moving relative to the apparatus
22
.
As shown in
FIGS. 2-3
, the illustrated combination pipe-extracting and core-breaking apparatus
22
includes an outer support member
34
and an inner carrier member
36
. In the illustrated embodiment, the inner carrier member
36
carries both a plurality of extractor jaw assemblies
38
and a plurality of core continuity breaking members
40
. It should be understood that the jaw assemblies and breaking members could be in other positions; for example, both sets of elements could be carried by an outer carrier member that moves relative to an inner support member.
As shown in
FIGS. 2-3
, in this embodiment, the outer support member
34
is supported near both ends by two sets of rollers
37
that are rotatably mounted on a pair of end rings
39
. The end rings
39
are fixed to the base
25
. The illustrated outer support member
34
has a first end
42
that is substantially open, a second end
44
and a central longitudinal axis
46
. The outer support member
34
is substantially hollow along substantially its entire length to the first end
42
, and has a cylindrical inner surface in the illustrated embodiment, although it should be understood that the invention is not limited to this particular shape.
The outer support member
34
may be made of any material suitable for the environment of use, such as mild steel having a wall thickness of about 1 inch, a length of about 66 inches and an outer diameter of about 12 inches. It should be understood that this material and these dimensions are provided by way of example only, and the present invention is not limited to any particular material or dimensions unless expressly set forth in the claims.
In the illustrated embodiment, the inner carrier member
36
has a first end
48
, a second end
50
, a central longitudinal axis
52
and an outer surface
54
. The illustrated inner carrier member
36
is received in the outer support member
34
in a telescoping fashion: it may be moved longitudinally along its axis
52
into and out of the outer support member
34
. The inner carrier member
36
extends out through the first end
42
of the outer support member
34
. The range of longitudinal motion of the inner member is illustrated in
FIGS. 2-3
. As shown in
FIG. 2
, when the inner carrier member
36
is extended out of the outer support member
34
, a portion of the inner member extends out beyond the first end
42
of the outer support member
34
, and a majority of the length of the inner member
36
is housed within the outer support member
34
. As shown in
FIG. 3
, when the inner carrier member
36
is retracted into the outer support member
34
, a shorter portion of the inner member extends out beyond the first end
42
of the outer support member
34
, and the majority of the length of the inner member
36
is housed within the outer support member
34
.
The inner carrier member
36
may be supported in the outer support member
34
, by roller bearings, or through any other support that allows relative longitudinal motion between the members
34
,
36
. The bearings preferably allow the inner carrier member to move longitudinally along the central longitudinal axes
23
,
46
,
52
. However, the support member
34
restrains pivotal movement of the carrier member
36
about an axis perpendicular to longitudinal axes
23
,
46
,
52
.
The inner carrier member
36
may be made of any material suitable for the environment of use, such as mild steel having a wall thickness of about 1 inch, a length of about 9 feet, and an outer diameter of about 10 inches. It should be understood that this material and these dimensions are provided by way of example only, and the present invention is not limited to any particular material or dimensions unless expressly set forth in the claims.
As shown in
FIGS. 4-6
, the inner carrier member
36
carries three spaced extractor jaw assemblies
38
in the illustrated embodiment. As shown in
FIG. 6
, the extractor jaw assemblies
98
extend radially outward from the outer surface
54
of the inner carrier member
36
. In the illustrated embodiment, the extractor jaw assemblies are evenly spaced on the inner carrier member
36
, although it should be understood that the number and spacing of the extractor jaw assemblies may be varied: fewer or more extractor jaw assemblies may be used; moreover, it is not necessary that the extractor jaw assemblies be positioned as shown and it is not necessary that the extractor jaw assemblies be evenly spaced from each other.
All of the extractor jaw assemblies
38
have the same structure in the illustrated embodiment, and only one will be described. It should be understood that the following description applies to all of the extractor jaw assemblies unless expressly noted.
As shown in
FIGS. 4-6
, each extractor jaw assembly
38
includes a support base
58
, two pair of pivotal extractor jaw tie members
60
, a jaw holder
62
and a jaw
64
. The support base
58
is fixed to the outer surface
54
of the inner carrier member
36
by welding or other suitable means of attachment, such as through use of mechanical fasteners like nuts and bolts. The two pair of extractor jaw tie plates
60
are rotatably attached to the support base
58
through pins
66
. The two pair of extractor jaw tie members
60
are also rotatably attached to the jaw holder
62
through pins
68
. The jaw holder carries the jaw
64
, which has a plurality of carbide inserts
70
in its bearing surface
72
.
As can be seen from a comparison of
FIGS. 4 and 5
, the pivotal connection provided by the extractor jaw tie members
60
and pins
66
,
68
allow the jaw support
62
and jaw
64
to be retracted away from the pipe inner surface
17
and extended toward the pipe inner surface
17
until the inserts
70
on the bearing surface
72
contact the inner surface
17
of the pipe
14
. The retracted position is shown in
FIGS. 2 and 4
and the extended position is shown in
FIGS. 3 and 5
.
To move the jaw
64
and jaw support
62
between the positions shown in
FIGS. 2-5
, an elongate tie plate
74
is pivotally connected at one end to one of the pins
68
that connects the upper pair of tie plates to the jaw support
62
. As shown in
FIGS. 2-3
, the opposite end of the elongate tie plate
74
is pivotally connected to a pin
76
that is mounted on a support structure
78
that is fixed to the outer support member
34
near the first end
42
of the outer support member
34
. Thus, as the inner member
36
is extended out of the outer support member
34
, the elongate tie bars
74
pull the jaws
64
into the retracted positions shown in
FIGS. 2 and 4
. As the inner member
36
is retracted into the outer support member
34
, the elongate tie bars
74
push the jaws into the extended positions shown in
FIGS. 3 and 5
so that the inserts
70
contact the inner wall surface
17
of the pipe
14
. The entire apparatus
22
may then be pulled back on the rails
24
,
26
by retracting the hydraulic drive
28
.
The inner member
36
may be extended and retracted through any suitable drive mechanism, such as a hydraulic cylinder shown schematically at
80
in
FIGS. 2-3
. The cylinder
80
may be connected to the second end
50
of the inner carrier member
36
. A suitable hydraulic cylinder is an Anker-Holth Hydraulic Rotating Cylinder, flange mount, with a 10 inch bore, a 4 inch stroke and with a non-rotating connection for the hydraulic fluid lines, shown at
81
in
FIGS. 2-3
, available from Anker-Holth of Brampton, Ontario, Canada. However, the invention is not limited to use of a drive mechanism, to a hydraulic cylinder, to this particular hydraulic cylinder mechanism or to one having these characteristics unless expressly called for in the claims. For example, other hydraulic cylinders could be used; motors, hydraulic or electric, and chains could also be used; and the carrier member
36
could be manually moved as well.
The outer member
34
and inner member
36
in the illustrated embodiment are both free to rotate about their central longitudinal axes
46
,
52
. However, there is no drive mechanism to rotate the outer and inner members
34
,
36
. Thus, if the pipe
14
is still rotating in the centrifugal casting machine
16
when the apparatus
22
enters the pipe and the jaws
64
are extended into contact with the pipe inner surface
17
, the outer and inner members
34
,
36
and the extractor jaw assemblies
38
may rotate with the pipe. However, it should be understood that the invention is not limited to such rotatable members unless expressly set forth in the claims.
The components of the extractor jaw assemblies
38
may be made of any material that is suited to the high temperature environment, although the extractor jaw assemblies
38
are generally not inside the hot pipe for a length of time that temperature is problematic. A suitable material is mild steel, but the invention is not limited to any particular material unless expressly set forth in the claims.
As shown in
FIGS. 4-6
, the inner carrier member
36
carries three spaced core continuity breaking members
40
in the illustrated embodiment. As shown in
FIG. 6
, the core continuity breaking members
40
extend radially outward from the outer surface
54
of the inner carrier member
36
. In the illustrated embodiment, the core continuity breaking members
40
are evenly spaced on the inner carrier member
36
, each core continuity breaking member
40
being substantially centered between a pair of extractor jaw assemblies
38
. It should be understood that the number and positions of the core continuity breaking members
40
may be varied: fewer or more core continuity breaking members may be used; moreover, it is not necessary that the core continuity breaking members be positioned as shown and it is not necessary that the core continuity breaking members be evenly spaced from each other. It is also not necessary that a core continuity breaking member be positioned between each pair of extractor jaw assemblies
38
, or centered between the extractor jaw assemblies
38
.
All of the core continuity breaking members
40
have the same structure in the illustrated embodiment, and only one will be described. It should be understood that the following description applies to all of the core continuity breaking members
40
unless expressly noted.
As shown in
FIGS. 4 and 5
, in the illustrated embodiment each core continuity breaking member
40
comprises a blade assembly. Each illustrated blade assembly includes a blade holder
82
and a blade
84
. As shown in
FIGS. 2-3
, each blade holder
82
is fixed to the outer surface
54
of the inner member
36
between the first end
48
of the inner member and the first end
42
of the outer support member
34
through welding or mechanical fasteners or the like. As shown in
FIGS. 2-5
, the blade holders
82
are positioned so that the blades
84
enter the pipe end after the retracted extractor jaw assemblies
38
have entered the pipe. The blade holders may be made of mild steel, although the invention is not limited to any particular material unless expressly set forth in the claims.
As shown in
FIGS. 4-6
, each blade
84
has a leading edge
86
that is sharpened for cutting through the sand core
20
as the core continuity breaking member
40
is moved into the pipe
14
. Each leading cutting edge
86
lies in a plane that intersects the central longitudinal axis
23
of the pipe
14
. Each blade
84
may be removably attached to the blade holder
82
through bolts
88
or the like. The blade
84
may be made of ¼ inch thick mild steel with the leading edge
86
ground to form the sharp cutting edge, for example. It should be understood that this material and dimension and illustrated shape are provided by way of example only, and the invention is not limited to such a blade or to use of a blade unless expressly set forth in the claims.
As shown in
FIGS. 4-6
, each illustrated blade
84
has a radial limit
90
. In the illustrated embodiment, the radial limit
90
of the blade
84
comprises an edge of the blade that is spaced furthest from the central longitudinal axis
52
of the inner member
36
. Generally, the blade holder
82
and blades
84
are sized, shaped and positioned so that the blades can cut through a substantial part of the sand core's radial dimension (the dimension between the inner surface and outer surface of the sand core) while insuring that the blades do not contact the inner surface
17
of the pipe
14
. If the blades were to contact the pipe's inner surface
17
, particularly in the area of the bell end
15
of the pipe
14
, the damage to the pipe could render it of unacceptable quality. Generally, the radial limit
90
of the blade may set to be at a distance of about ⅛ inch from the inner surface
17
of the pipe, with a tolerance of plus or minus {fraction (1/16)} inch. However, it should be understood that this distance and tolerance are provided by way of example only, and that the present invention is not limited to this distance and tolerance unless expressly set forth in the claims. Thus, although the claims may refer to the radial limits of the blades or to the core continuity breaking member being spaced from the inner surface of the pipe to prevent contact between the core continuity breaking member and the inner surface of the pipe, such references should not be interpreted as any particular distance or tolerance.
In the embodiment illustrated in
FIGS. 2-6
, the blade holder
82
also includes an extension that trails the blades
84
as the blades enter the pipe. As shown in
FIGS. 4-5
, the blade holder extension includes a pancake-breaking-portion
94
that comprises an edge that is substantially perpendicular to the central longitudinal axis
52
of the inner member
36
and substantially parallel to the outer surface of the pancake
96
of the sand core
20
. The pancake
96
of the sand core
20
is a portion that extends over and defines the outer rim of the bell end
15
of the pipe
14
. As shown in
FIGS. 4-5
, the pancake
96
may extend radially out beyond the inner diameter of the pipe
14
and mold
18
, so that the blades
84
may not cut through a substantial part of the pancake
96
. The pancake-breaking portion
94
is provided to break the continuity of the sand core's pancake
96
.
A first alternate embodiment of a blade assembly is illustrated in
FIGS. 7-8
. As shown in
FIG. 7
, the blade holder need not include the extension and pancake-breaking portion
94
of the first embodiment, and may simply bear the blade
84
a.
As shown in
FIG. 8
, a separate extension
102
a
may be provided to be attached to the blade holder as desired and in any suitable manner.
Another alternative embodiment of a blade assembly is illustrated in FIG.
9
. As shown in
FIG. 9
, the blade holder
100
b
need not be shaped like that shown in the embodiments of
FIGS. 1-8
. For a different type of pipe end, with a different type of sand core, the blade holder
100
b
may be shaped as desired to break the continuity of the sand core in the most efficient manner. Other variations are possible; for example, additional blades may be included on the illustrated blade holder
100
b.
Another alternative embodiment of a core continuity breaking member is illustrated in FIG.
10
. As shown in
FIG. 10
, the core continuity breaking member
40
c
need not include a portion for breaking the continuity of the inner part of the sand core. Instead, the core continuity breaking member
40
c
may include a pancake breaking portion
94
c
alone.
Other variations are possible. For example, the core continuity breaking members
40
may be attached to the extractor jaw assemblies
38
instead of being spaced from the extractor jaw assemblies
38
as shown. Moreover, although the illustrated embodiment uses three identical core continuity breaking members
40
, all of the core continuity breaking members on one carrier member need not be the same. For example, there could be separate core continuity breaking members for breaking the continuity of different parts of the sand core.
Although in the illustrated embodiment the core continuity breaking members have a fixed radial dimension, they could be mounted to structures to allow them to be radially retracted and extended to cut through the sand core. Thus, the continuity of the sand core can be broken when there is no relative longitudinal movement between the pipe and the carrier member by radially extending the core breaking members.
It should be understood that in any of the embodiments, the pancake-cutting portion may comprise a separate blade element that is attached to the blade holder. In addition, since the function of the apparatus is to break the continuity of the sand core so that it will either fall out of the pipe or be more easily removed from the pipe, it is not necessary to provide a blade at all. Moreover, instead of an assembly, the core continuity breaking member
40
could comprise a simple integral plate that plows through and breaks the continuity of the sand core. Preferably, the continuity of the sand core is broken at several locations, as in the illustrated embodiment, but the present invention is not limited in the number of breaks or breaking members unless expressly set forth in the claims.
Many variations in the structure of the apparatus are possible and should be understood as falling within the scope of the invention unless expressly excluded. For example, the carrier member could comprise an outer tube and the support member could comprise an inner tube. Or, instead of a single elongate outer tube serving as a support member, a series of spaced brackets or tubes could be used for support of the carrier member. The carrier member could have another shape as well, and need not be tubular in shape.
As shown in
FIG. 6
, the system includes pipe supporting rollers. The illustrated system includes retractable hourglass-shaped rollers
106
for initially supporting the pipe as it exits the pipe casting machine
16
. After the entire pipe has been drawn out of the casting machine, the hourglass-shaped rollers
106
may be retracted and the pipe supported on rotatable rollers
108
. The rotatable rollers
108
may be rotated to rotate the pipe to maintain the roundness of the hot pipe. The pipe may then be moved by a crane or other device to a position downstream in the plant, such as to the annealing oven or to a cleaning station for further cleaning of the waste sand from the bell end of the pipe.
In operation, the sand core
20
is placed at the bell end of the mold
18
and the pipe
14
is centrifugally cast in the casting machine
16
, with metal forming around the outer surface of the sand core
20
. The pancake
96
of the sand core
20
seals the end of the mold. After the pipe is cast, the drive mechanism
28
is activated to move the combination pipe-extracting and core-breaking apparatus
22
longitudinally on the rails
24
,
26
toward the casting machine
16
. During this longitudinal movement of the apparatus
22
, the inner member
36
is kept in the extended position shown in
FIGS. 2 and 4
so that the extractor jaws
64
are retracted. With the jaws retracted, the first end
48
of the inner member
36
enters the bell end
15
of the pipe
14
, followed by the retracted jaws
64
, followed by the blade holders
82
and the blades
84
. The core continuity breaking members
40
are sized, shaped and positioned so that at least part of the core continuity breaking member
40
contacts the sand core
20
during this relative longitudinal movement between the core continuity breaking member
40
and the pipe
14
to break the continuity of at least a part of the sand core
20
. When the core continuity breaking members
40
include blades as shown, the sharpened leading edges
86
of the blades slice through a substantial part of the radial dimension of the sand core. The radial limits
90
of the blades stay spaced from the inner surface
17
of the pipe so that the inner surface is not scored or damaged by the blades
84
. The blade holders
82
are also spaced from the inner surface
17
of the pipe throughout this longitudinal movement of the apparatus
22
and core continuity breaking members
40
.
Forward longitudinal movement of the apparatus
22
and the blade holder also causes the pancake-breaking portions
94
of the blade holders
82
to plow through portions of the pancake. This forward longitudinal movement of the apparatus stops before the pancake-breaking portions
94
of the blade holders
82
contact the rim at the bell end of the pipe. As shown in
FIGS. 2-3
, the rails
24
,
26
or some other structure may include stop blocks
110
to block forward movement of the apparatus
22
at a preselected position. The stop blocks
110
could be fixed in position in any standard manner, such as by welding. A positive stop may be fixed to the casting machine, such as shown at
112
in
FIGS. 2-3
; the length of this stop
112
sets a predetermined longitudinal distance between the end of the pipe in the casting machine and the blade holders
82
to prevent contact between the blade holders
82
and pancake-breaking portion
94
with the end of the pipe
14
. It should be understood that other devices could be used as well, such as a position sensor that is tied through a logic element to control the drive mechanism
28
. It might also be desirable to include a position sensor to sense the position of some part of the mold
18
, sand core
20
or pipe
14
and to control movement of the drive mechanism
28
through a logic element based upon the sensed position of the mold
18
, sand core
20
or pipe
14
.
After the apparatus has stopped its forward longitudinal movement, the hydraulic mechanism
80
may be activated to withdraw the inner carrier member
36
into the outer support member
34
. As the inner carrier member
36
is withdrawn, the elongate tie plates
74
force the jaws to extend outward and the jaw bearing surface
72
or jaw inserts
70
contact the inner surface
17
of the pipe wall. The drive mechanism
28
may then be activated to pull the entire apparatus
22
and pipe
14
longitudinally away from the casting machine
16
. As the pipe
14
is pulled from the mold
18
in the centrifugal casting machine
16
, the pipe
14
is supported on the hourglass-shaped rollers
106
.
Since the blades
84
have cut though substantial parts of the radii of the sand core, breaking its continuity within the pipe, and since the portions
94
of the blade holder
82
have broken the continuity of the sand core pancake
96
at several locations, the structural integrity of the sand core is destroyed and it falls from the pipe. The hourglass rollers
106
may be retracted so that the pipe then rests on the rollers
108
, which may be rotated to rotate the pipe to preserve pipe roundness. The pipe may then be moved to another station for further cleaning of the bell end of the pipe and for treatment of the pipe, such as heat treatment in an annealing furnace.
For different diameters of pipe, the apparatus
22
may have interchangeable extractor heads. Each extractor head could comprise the inner carrier member
36
, the set of extractor jaw assemblies
38
connected to the inner carrier member
36
, and the core continuity breaking members
40
fixed to the inner carrier member
36
. The elongate tie plates
74
could also be part of each extractor head. The shape, dimensions and number of the extractor jaw assemblies
38
and core continuity breaking members
40
attached to the inner carrier member
36
could be varied depending upon the pipe dimensions. The extractor heads could be changed by removing the pins
68
connecting the elongate tie members
74
to the extractor jaw assemblies
38
and then sliding the entire inner carrier member
36
out of the outer support member
34
and then sliding a new extractor head into the outer support member
34
and connecting the elongate tie members
74
to the extractor jaw assemblies
38
of the new extractor head through the pins
68
. Alternatively, pins
76
could be removed and the elongate tie members
74
changed with the extractor head.
Alternate extractor heads are also possible. For example, each extractor head could comprise a relatively short sleeve section that telescopes over the first end
48
of the inner carrier member
36
and is then fixed at the end of the inner carrier member with set screws, clamps or the like. The extractor jaw assemblies
38
and core continuity breaking members
40
could be fixed to the short sleeve section by welding or the like. Alternatively, the extractor jaw assemblies
38
and core continuity breaking members could be individually mounted on the end of the inner carrier member
36
and removably fixed thereon through bolts, set screws, clamps or through some other mechanical mounting mechanism. Slots could be formed in the inner carrier member
36
to receive the assemblies
38
and members
40
.
It should be understood that the present invention is not intended to be limited to any particular type of extractor head assembly unless expressly set forth in the claims. It should also be understood that references to the extractor jaw assemblies
38
and core continuity breaking members
40
being fixed to the carrier member
36
or to the outer surface of the carrier member
36
are intended to include embodiments wherein the extractor jaw assemblies
38
and core continuity breaking members
40
are fixed directly to the carrier member
36
by welding or some mechanical connection, as well as though connection to another element such as a sleeve that is itself fixed to the carrier member
36
through welding or through some mechanical connection. It should also be understood that references to the extractor jaw assemblies
38
and core continuity breaking members
40
being fixed to the carrier member
36
or to the outer surface
54
of the carrier member
36
are intended to include removable connections such as provided through nuts and bolts, screws or other mechanical connections.
Although described and shown in the form of an apparatus and method that combines pipe extraction with core breaking, the invention is not intended to be limited to such combinations unless expressly set forth in the claims. For example, it may be desirable in some instances to perform these operations in separate steps: one apparatus could be provided for pipe extraction and a second apparatus may be provided for breaking the sand core, with the step of breaking the sand core either preceding or following extraction of the pipe from the mold.
The principles of the present invention may be applied to other types of pipe casting and extraction systems. For example, instead of moving the extraction assemblies and core breaking assemblies longitudinally into the pipe, the pipe in the mold in the casting machine could be moved longitudinally toward and over the extraction assemblies and core breaking assemblies. The invention encompasses both two-stroke and four-stroke centrifugal casting machines. The invention is intended to encompass any relative longitudinal movement between these elements unless the claims expressly call for movement of a particular element in a particular direction.
It should be understood that although described in context of making cast iron pipe that is later heat-treated to form ductile iron pipe, the principles of the present invention may be applied to the production of other cast metal pipe and other cast metal objects.
The apparatus and method of the present invention may be computer controlled. A computer or programmable logic component may be connected to receive input such as an electrical signal from the casting machine or from a sensor such as a limit switch to sense when the casting machine has reached a preset position. The programmable logic component can be connected through outputs to control operation of the drive mechanism
28
to move the entire apparatus
22
along the rails
24
,
26
and to control operation of the drive mechanism
80
to move the member
36
. The programmable logic component could also be connected to control operation and movement of the pipe supporting rollers
106
,
108
. Alternatively, a separate programmable logic component could control the pipe supporting rollers
106
,
108
.
A commercially-available programmable logic component may be used. A suitable programmable logic and motion control system is available from Allen-Bradley Co./Rockwell Automation, of Milwaukee, Wis. and other locations, with standard logic suitably programmed, as will be understood by those skilled in the art. It is expected that the supplier would be consulted for selection of an appropriate model of component. A standard PLC with standard logic may be programmed by one skilled in the programming art, such as an electrical engineer, or more sophisticated programming could be developed if desired. It should be understood that this computer control is identified for purposes of illustration only, and that the invention is not limited to use of programmable logic components, to components from this supplier, or to any particular program, computer or PLC.
While only a specific embodiment of the invention has been described and shown, it is apparent that various alterations and modifications can be made therein. It is, therefore, the intention in the appended claims to cover all such modifications and alterations as may fall within the scope and spirit of the invention. Moreover, the invention is intended to include equivalent structures and structural equivalents to those described herein.
Claims
- 1. An apparatus for breaking the continuity of an annular sand core in the interior of a hollow cast metal pipe,the pipe having an inner surface with an inner diameter and a central longitudinal axis; the annular sand core in contact with a portion of the interior surface of the hollow cast metal pipe; the apparatus comprising: a carrier member, a support member supporting at least a part of the carrier member, and at least one core continuity breaking member extending from the carrier member; the carrier member being longitudinally moveable along the central longitudinal axis of the pipe such that a portion of the carrier member enters the interior of the hollow cast metal pipe; the core continuity breaking member being sized, shaped and positioned so that at least part of the core continuity breaking member contacts the sand core during relative longitudinal movement between the core continuity breaking member and the pipe to break the continuity of at least part of the sand core, wherein at least one of the support and carrier members is free to rotate with any rotation of the pipe about the central longitudinal axis of the pipe, the support member restraining pivotal movement of the carrier member about another axis.
- 2. The apparatus of claim 1 wherein the sand core includes a pancake portion on the exterior of the pipe and the core continuity breaking member includes a portion for contacting and breaking the continuity of at least a part of the pancake of the sand core.
- 3. The apparatus of claim 1 wherein the sand core includes a portion within the interior of the pipe and the core continuity breaking member includes a portion for breaking the continuity of the portion of the sand core within the interior of the pipe during relative longitudinal movement between the pipe and the core continuity breaking member.
- 4. The apparatus of claim 3 wherein the core continuity breaking member is within the interior of the pipe at some times and outside of the interior of the pipe at other times, the core continuity breaking member being spaced from the inner surface of the pipe throughout the relative longitudinal movement of the carrier member and the pipe to prevent contact between the core continuity breaking member and the inner surface of the pipe.
- 5. The apparatus of claim 3 wherein the core continuity breaking member comprises a blade assembly including a blade holder fixed to the carrier member and a blade removably attached to the blade holder.
- 6. The apparatus of claim 5 wherein the blade has a radial limit that is spaced from the inner surface of the pipe.
- 7. The apparatus of claim 3 wherein the sand core includes an integral pancake portion on the exterior of the pipe and wherein the core continuity breaking member includes a portion for contacting and breaking the continuity of at least a part of the pancake of the sand core.
- 8. The apparatus of claim 1 further including an extractor assembly carried by the carrier member at a position spaced from the core continuity breaking member.
- 9. The apparatus of claim 1 wherein:the support member comprises an elongate tube with a first end, a second end and a longitudinal axis, the support member being hollow along at least a part of its length to the first end and the first end of the support member being at least partially open; and the carrier member having a first end and a second end, at least a part of the carrier member being carried within the support member, the carrier member extending through the opening in the first end of the support member, the first end of the carrier member and at least part of the carrier member extending beyond the first end of the support member.
- 10. The apparatus of claim 9 wherein the apparatus is longitudinally moveable and the carrier member is longitudinally moveable into and out of the support member.
- 11. The apparatus of claim 1 wherein the carrier member has an outer surface and a longitudinal axis and the core continuity breaking member extends radially outward from the outer surface of the carrier member.
- 12. The apparatus of claim 1 wherein there are a plurality of core continuity breaking members extending radially outward from the carrier member.
- 13. The apparatus of claim 12 wherein there are a plurality of extractor assemblies extending radially outward from the carrier member.
US Referenced Citations (4)
Foreign Referenced Citations (3)
Number |
Date |
Country |
27 31 802 |
Feb 1979 |
DE |
2 707 901 |
Jan 1995 |
FR |
343652 |
Feb 1931 |
GB |