Tubular Facing Connected End To End, E.g., Bell Or Spigot, Etc. Patents (Class 249/100)
  • Patent number: 9469053
    Abstract: A pallet includes a rigid body that supports a concrete product and a polymer layer that corresponds to a geometry of the concrete product within a predetermined tolerance. One or more flanges with apertures are provided with the rigid body for the polymer layer to attach thereto. The polymer layer can extend outward from the rigid body to form a portion of the dimensions for the concrete product within predefined tolerances.
    Type: Grant
    Filed: January 23, 2014
    Date of Patent: October 18, 2016
    Assignee: Hawkeye Concrete Products Co.
    Inventor: Claudio Subacchi
  • Patent number: 9463994
    Abstract: A device for manufacturing an optical preform by means of an internal vapor deposition process including an energy source, a hollow substrate tube having a supply side and a discharge side and the energy source being moveable along a length of the hollow substrate tube, and an elongation tube connected to the hollow substrate tube at the discharge side thereof, wherein the hollow substrate tube extends into an interior of the elongation tube and an internal diameter of the elongation tube is at least 0.5 millimeters larger than an external diameter of the hollow substrate tube.
    Type: Grant
    Filed: May 19, 2015
    Date of Patent: October 11, 2016
    Assignee: Draka Comteq B.V.
    Inventors: Igor Milicevic, Johannes Antoon Hartsuiker, Mattheus Jacobus Nicolaas Van Stralen, Gertjan Krabshuis, Eric Aloysius Kuijpers
  • Patent number: 8512027
    Abstract: A belling machine (1) forms end sockets equipped with an integrated seal on pipes (3) made of thermoplastic material using a forming mandrel (4) on which an annular seal (5) was previously placed, diametrically expanded, coaxially and in a predetermined position. A loader (8) for loading the annular seal (5) on the mandrel (4) is able to move between a arming position, in which the loader is spaced from the belling axis (b) and does not interfere with the mandrel (4) movement along the belling axis (b), and a loading position, in which the loader is coaxial with the belling axis (b) and is located between the mandrel (4) back position, disengaged from the pipe (3) and the mandrel (4) forward position, inserted in the end (30) of the pipe (3). An annular seal (5) is placed in a positioner (10) which holds it in an operating position for the action of an arming device (9).
    Type: Grant
    Filed: March 15, 2011
    Date of Patent: August 20, 2013
    Assignee: Sica S.p.A.
    Inventors: Giorgio Tabanelli, Patrik Altini
  • Patent number: 8024015
    Abstract: A mobile device having a housing and operating on power supplied from the battery loaded in the battery chamber including: a pair of walls of the housing having hook receiving portions formed a groove; a battery lid covering the battery chamber so as to be freely detached; a pair of positioning hooks serving to position the battery lid by entering the grooves of the corresponding hook receiving portions; overhanging edges serving to regulate position of the cover lid; and a waterproof gasket fixed to the battery chamber side of the cover lid so as to be in contact with all sides of the battery chamber.
    Type: Grant
    Filed: October 20, 2008
    Date of Patent: September 20, 2011
    Assignee: Fujitsu Limited
    Inventors: Tatsuhito Araki, Hiroaki Matsuda, Yoshiya Matsumoto, Manabu Sotodate, Wataru Murata, Ken Shoji, Ryo Hattori
  • Patent number: 7112055
    Abstract: An apparatus for heating and setting elements of a stent. The apparatus is a mandrel having a central core cylinder with an outer surface including a plurality of raised forms and gaps in-between the raised forms. The mandrel also includes a first and second outer cylinder, each having a curved radial end with a cut-out design similar to the shape of the plurality of raised forms. Once a stent is placed on the central core cylinder, the first and second outer cylinders are positioned on the central core cylinder such that the curved radial ends of the first and second outer cylinders align with the plurality of raised forms, shaping the stent.
    Type: Grant
    Filed: July 2, 2002
    Date of Patent: September 26, 2006
    Assignee: Endovascular Technologies, Inc.
    Inventors: Boris Anukhin, Masoud Molaei, David T. Pollock
  • Patent number: 6817589
    Abstract: As a part of the manufacture of concrete products, such as concrete pipe, manholes and the like, the joint rings applied during the casting process much be removed. The invention relates to a joint ring removal system in which a vertically oriented concrete product, containing a joint ring, is gripped to hold the product stationary while a joint ring pulling force is applied. Then, a shocking force is applied laterally to the joint ring to free it from the concrete joint. The amount of pulling force applied to the joint ring is less than that required to separate the joint ring from the concrete while the shocking force is applied in a direction transverse to the pulling force so that no harmful tensile shocking forces are transmitted to the concrete joint. The pulling force on the joint ring is variably applied and timed with the shocking force.
    Type: Grant
    Filed: February 19, 2002
    Date of Patent: November 16, 2004
    Assignee: Hawkeye Concrete Products Co.
    Inventors: Jon A. Schmidgall, Ronald D. Schmidgall, David Stoller
  • Patent number: 6789398
    Abstract: A heat source is formed within one piece of a multi-piece mold designed to shape a glass tube. The one piece of the mold can then be used as a source of intense heat to render the glass malleable and to also contribute to shaping the tube in conformance with the mold. In one embodiment, the heat source includes channels formed throughout the one piece of mold for distributing a gas therethrough with jets of gas emanating from the inner surface of the mold piece for heating the tube to be shaped to a desired temperature. In apparatus embodying the invention, there is no need for a separate torch and for moving the torch during the shaping process. Also, in accordance with the invention, better control of the heat supplied to the tube being shaped is obtained.
    Type: Grant
    Filed: February 2, 2000
    Date of Patent: September 14, 2004
    Assignee: CommScope Solutions Properties, LLC
    Inventors: Bassel H. Daoud, David S. Kerr, Peter M. Mueller, Ivan Pawlenko, Larry Samson
  • Patent number: 6736365
    Abstract: A three piece full port ball valve for use with a form for producing a cast concrete article is provided wherein the housing of the valve has been modified by creating openings through the valve housing to access the flow opening in the ball member for clearing concrete slurry therefrom after the form has been filled. Additional openings in the housing at other locations can be created for cleaning around the ball member and the inside of the housing.
    Type: Grant
    Filed: January 25, 2002
    Date of Patent: May 18, 2004
    Assignee: Naams, LLC
    Inventors: Alma L. Staskiewicz, William S. Long, III
  • Patent number: 6536239
    Abstract: A mold for shaping the end region and the opening at a selected end of a first, hollow, generally cylindrical, glass tube to enable a second tube, of smaller diameter than the first tube, to be inserted snuggly a first distance within the selected end of the first tube resulting in the two tubes nesting and being self-centered. The mold includes two complementary elongated side pieces having inner side surfaces for, when joined, encircling the periphery of the first tube along a given portion of its selected end region, and an end cap with a cylindrical stub for insertion within the opening of the first tube at its selected end.
    Type: Grant
    Filed: February 2, 2000
    Date of Patent: March 25, 2003
    Assignee: Fitel USA Corp.
    Inventors: Peter M. Mueller, Ivan Pawlenko
  • Patent number: 6395213
    Abstract: A form for producing a cast concrete article can have a core at least partially surrounded by an outer jacket thus defining a cavity between an outer surface of the core and an inner surface of the outer jacket. A header can be provided generally sealed against the top of the outer jacket and around the top of the core. A bottom member can also be provided generally sealed against the bottom of the outer jacket and around the bottom of the core. The cavity thus being defined by the outer jacket, core, header and bottom member. A fill port, which can be selectively opened or closed, can communicate with the cavity through the outer jacket for filling the cavity with liquid concrete using a pump. Vents can be provided in the header for evacuating air when the cavity is being filled with liquefied concrete so that voids in the finished article are substantially eliminated.
    Type: Grant
    Filed: June 24, 1999
    Date of Patent: May 28, 2002
    Inventors: Alma L. Staskiewicz, William S. Long, III
  • Patent number: 5648108
    Abstract: A production system for automatically casting hollow bodies, in particular of concrete, in a casting mold, which comprises an inner mold (2), an outer mold (1), a bottom ring (3), and a top ring (4). Separate top rings (4) are used for the production, which remain on the top end of the pipe until the concrete has set sufficiently, to ensure that the shape and tolerances of the top end of the pipe are retained after casting. The system moreover includes a clamping chuck (15) for retaining the top ring during casting. The clamping chuck is equipped with a clamping device that includes a ring-shaped flexible hose and a slotted spring ring. When the hose is filled with compressed air from a compressed air source, it clamps the spring ring together around a gripping ring on the top ring.
    Type: Grant
    Filed: August 7, 1995
    Date of Patent: July 15, 1997
    Assignee: Pedershaab A/S
    Inventor: Johannes Hvidegaard
  • Patent number: 5286440
    Abstract: A method and apparatus for the production of a symmetrical oval concrete pipe including an oval male joint member and an oval female joint member formed on opposite ends of an oval pipe body including an outer jacket and an inner core disposed in spaced relationship relative to each other to form the oval pipe body therebetween; an upper pallet and a lower pallet configured to form the oval male joint member and the oval female joint member respectively, and a pallet positioning structure configured to engage the upper pallet and the lower pallet to operatively position the upper pallet and lower pallet relative to the outer jacket and inner core such that corresponding points on the upper pallet and the lower pallet are aligned relative to each other whereby corresponding points of the oval male joint member and the female joint member are aligned relative to each other.
    Type: Grant
    Filed: January 14, 1993
    Date of Patent: February 15, 1994
    Inventor: Roger Beacom
  • Patent number: 5251867
    Abstract: A header pallet for the manufacture of the spigot of a concrete pipe to receive a sealing gasket during assembly of a pipe line including an outer header ring having an end leg portion and a side leg portion to cooperatively form a substantially L-shaped profile wherein the intersection of the inner surface of the end leg portion and the inner surface of the side leg portion are contoured to form a concave surface and a shoulder is formed on the inner surface of the side leg portion in spaced relationship relative to the concave surface, a removable compressible intermediate ring having a substantially arcuate profile including an outer convex surface, and a removable inner snap ring having a substantially rectilinear profile such that the removable inner snap ring is placed to engage the shoulder in spaced relationship relative to the end leg portion and the removable compressible intermediate ring is press fitted between the removable inner snap ring and the end leg portion with the outer convex surface the
    Type: Grant
    Filed: April 9, 1992
    Date of Patent: October 12, 1993
    Inventor: Roger Beacom
  • Patent number: 5238384
    Abstract: The components forming the layers of a composite pipe are successively introduced into a rotary drum (1). Initially, a plastic reinforcing layer (8), including a fibre reinforcement, is introduced into the drum, the ends of the drum (1) being bounded by rings. A concrete core layer (16) is then introduced and the length of the core layer (16) is shortened relative to that of the drum (1) by shaping rings fixed to the drum ends. The shaping rings are then replaced by other shaping rings (20, 21) so that, on either side of the core layer (16), two annular spaces (22, 23) are formed which are filled by a socket material (24, 25) of the same composite as the reinforcing layer (8). Thus, at one pipe end a socket end (28) is formed and at the other pipe end a spigot end (30) is formed, each such end being located within the composite pipe wall thickness. After introducing a second reinforcing layer (26), the production of the composite pipe is completed.
    Type: Grant
    Filed: July 23, 1991
    Date of Patent: August 24, 1993
    Assignee: Von Roll AG
    Inventors: Peter Hartmann, Bernhard Bergmann
  • Patent number: 5229024
    Abstract: The invention relates to seals on equipment used to make concrete pipe. Such equipment includes two generally vertical cylindrical surfaces, a core and a mold, with upper and lower end forming rings. The lower end forming ring, a pallet, has inner and outer vertical surfaces. Seals of the present invention are formed by using two hollow tubes of soft rubber. The tubes are housed in lower portions of the core and the mold so that they are in alignment with the inner and outer surfaces of the pallet. The tubes are pressurized into tight engagement with the pallet to prevent the outward flow of slurry from the space between the core and the mold.
    Type: Grant
    Filed: July 19, 1991
    Date of Patent: July 20, 1993
    Assignee: International Pipe Machinery Corp.
    Inventor: Mark R. Corbin
  • Patent number: 5215673
    Abstract: An apparatus for the production of a symmetrical oval concrete pipe including an oval male joint member and an oval female joint member formed on opposite ends of an oval pipe body having a form including an outer jacket and an inner core disposed in spaced relationship relative to each other to form the oval pipe body therebetween; an upper pallet and a lower pallet configured to form the oval male joint member and the oval female joint member respectively, and a pallet positioning structure configured to engage the upper pallet and the lower pallet to operatively position the upper pallet and lower pallet relative to the outer jacket and inner core such that corresponding points on the upper pallet and the lower pallet are aligned relative to each other whereby corresponding points of the oval male joint member and the female joint member are aligned relative to each other.
    Type: Grant
    Filed: February 3, 1992
    Date of Patent: June 1, 1993
    Inventor: Roger Beacom
  • Patent number: 5082614
    Abstract: The components forming the layers of a composite pipe are successively introduced into a rotary drum (1). Initially, a plastic reinforcing lyaer (8), including a fiber reinforcement, is introduced into the drum, the ends of the drum (1) being bounded by rings. A concrete core layer (16) is then introduced and the length of the core layer (16) is shortened relative to that of the drum (1) by shaping rings fixed to the drum ends. The shaping rings are then replaced by other shaping rings (20, 21) so that, on either side of the core layer (16), two annular spaces (22, 23) are formed which are filled by a socket material (24, 25) of the same composite as the reinforcing layer (8). Thus, at one pipe end a socket end (28) is formed and at the other pipe end a spigot end (30) is formed, each such end being located within the composite pipe wall thickness. After introducing a second reinforcing layer (26), the production of the composite pipe is completed.
    Type: Grant
    Filed: December 22, 1989
    Date of Patent: January 21, 1992
    Assignee: Peter Hartmann Beteiligungen AG
    Inventors: Peter Hartmann, Bernhard Bergmann
  • Patent number: 4708632
    Abstract: A mould which is used for the production by injection moulding of fittings which have an inner annular groove includes a divisible outer mould, a mould core and a mould ring. The mould core has a plurality of segments which can be folded together. In order to ensure with absolute reliability that the fitting does not remain clinging to the mould ring during removal of the fitting from the mould, the mould ring is connected to the mould core and is withdrawn together with the mould core from the fitting.
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: November 24, 1987
    Assignee: I.F.W.-Industrie-Formen und Werkzeugbau-Manfred Otte Gesellschaft m.b.H. & Co. KG.
    Inventors: Erich Mitteregger, Ernst Schwaiger
  • Patent number: 4614324
    Abstract: A mold is provided for use in the production of concrete pipe sections. The mold has an inner mold part including an arch-shaped mold member; a pair of substantially L-shaped side mold members each flexibly connected to an adjacent end of the arch-shaped mold member and extending along the side portions of the mold and with parts extending inwardly across the bottom portion of the mold, and a separable mold member detachably connected between the inwardly extending parts of the L-shaped side mold members. The parting of the mold from the product is accomplished by removing the separable mold member, and urging the L-shaped side mold members inwardly. Provided also is a mold for use in the production of mitred concrete pipe sections comprising an upper inclined pipe and a lower inclined pipe which are connected to each other at their mitred surfaces. A mold is also provided for producing concrete pipe elbows having partition plates adapted to produce elbows of various arcuate sizes.
    Type: Grant
    Filed: May 2, 1984
    Date of Patent: September 30, 1986
    Assignees: Nippon Pressed Concrete Co., Ltd., Nippon Zenith Pipe Co., Ltd.
    Inventors: Kiichi Yamashita, Junpei Tanizawa, Takao Iwasaki
  • Patent number: 4522669
    Abstract: A mould portion and/or protective element of the type consisting of a material subjected to deformation is disclosed. A method and a device for manufacturing such a mould portion and/or protective element are also disclosed.The mould portion and/or protective element is preferably intended to be used as a mould portion in moulding an article and/or as a protective element to prevent access of soil and water to a surface portion of the article during transportation and storage thereof.Such materials subjected to dimensional changes as can be used as mould portions and/or protective elements present the advantages of being inexpensive and permitting removal of the article without difficulty. One such material is for example cellular plastics. The dimensional changes, however, have entailed so great difficulties in using mould portions and/or protective elements of such materials that they have made the use of the material impossible.
    Type: Grant
    Filed: September 1, 1982
    Date of Patent: June 11, 1985
    Assignee: Forsheda AB
    Inventors: Olof Nordin, Soren Forsberg
  • Patent number: 4449912
    Abstract: An apparatus for manufacturing concrete pipes having a molding flask provided with a specially formed end ring on the bell end side. The apparatus further includes a device for detaching this end ring and another device disposed at the spigot end side and allotted for thrusting a hardened concrete pipe out of the molding flask.
    Type: Grant
    Filed: October 22, 1982
    Date of Patent: May 22, 1984
    Inventor: Mitsuharu Ogura
  • Patent number: 4418885
    Abstract: A improved apparatus for molding pipes is dislosed. A hood of convex shape having an outer surface corresponding to the shape of the interior of the pipe and has an annular rim on the widest part thereof and a molding shank rigidly attached to the narrowest part of the hood. A flat annular washer is support on the rim and being separable therefrom to provide a flat terminal end for the molded pipe.
    Type: Grant
    Filed: November 24, 1981
    Date of Patent: December 6, 1983
    Inventor: Angel B. Serrano
  • Patent number: 4305564
    Abstract: The invention relates to the technical problem of providing a simple, efficient and easily operable locking mechanism to releasably clamp the bottom ring to the lower edge of the outer mould in a casting mould for the production of concrete or similar pipes in an upright position. With this in view the locking mechanism comprises a radially slotted, resilient locking ring which by means of an opening and closing mechanism is movable between a locking position in which it engages beneath the outer edge portion of the bottom ring and seals said portion tightly against the lower edge of the outer mould, and a free position in which the inner diameter of the locking ring is larger than the outer diameter of the bottom ring so as to enable said locking ring to pass free of the bottom ring when the recently cast pipe is separated from the mould.
    Type: Grant
    Filed: November 3, 1980
    Date of Patent: December 15, 1981
    Assignee: Pedershaab Maskinfabrik A/S
    Inventor: Johannes Jensen
  • Patent number: 4151246
    Abstract: Pipes of short length are moulded in a vertical pipe-making machine by locating a series of rings in a circular mould to divide the length of the mould into several compartments, the compartments are filled with settable material, to form a pipe with the rings embedded in it, and the pipe is divided into short lengths by removing the rings. The rings are held in position by stops projected through the wall of the mould into the moulding space, which are withdrawn prior to demoulding. The rings and reinforcement cages are assembled on a jig that is withdrawn before the pipe is moulded.
    Type: Grant
    Filed: May 9, 1977
    Date of Patent: April 24, 1979
    Assignee: Vianini Pipes (Proprietary) Limited
    Inventors: Dudley R. Lester, Leslie D. Reeves
  • Patent number: 4134568
    Abstract: A form assembly for making concrete product, as concrete pipes. The form assembly has a pair of upright outer forms comprising cylindrical jackets. The cylindrical jackets are secured to each other with connectors. First latch structures connected to the cylindrical jackets hold the jackets in closed positions. The first latch structures are movable to release positions to expand the jackets to open positions. Pallets are located in the lower ends of the jackets. Second latch structures mounted on the lower ends the jackets are operable to hold the pallets in assembled relation with the jackets. Control linkage operably connected to both the first latch structures and second latch structures is operable to sequentially operate the first and second latch structures to open and close the jackets and release and hold the pallets.
    Type: Grant
    Filed: April 7, 1977
    Date of Patent: January 16, 1979
    Assignee: Hydrotile Canada Limited
    Inventor: Alfred W. Christian
  • Patent number: 4123034
    Abstract: A box form used in a dry cast system for making a concrete box culvert. The form has a pair of wall sections secured together with a pair of corner units. The corner units can be removed from the wall sections and replaced with different sized corner units to change the size of the complete form. Spacers can be interposed between the corner units and wall sections to change the wall thickness of the box culvert. The form is carried on a pallet assembly having members for accommodating lift structures of a fork life vehicle. The pallet assembly is a rectangular structure having a stepped pallet and upright guide members. The guide members cooperate with rails on lower portions of the form to locate the form on the pallet assembly. The pallet assembly and form surround a box core providing a box chamber for receiving the concrete mix forming a concrete box culvert.
    Type: Grant
    Filed: February 14, 1977
    Date of Patent: October 31, 1978
    Assignee: BC Pausch, Inc.
    Inventors: Elmer Kenneth Crunk, John W. Craft
  • Patent number: 4123033
    Abstract: Improved apparatus for forming hollow cylindrical pipes of reinforced concrete wherein the pipe is formed in a vertical position and the principle components for forming the pipe comprise a bottom pallet and saddle, an outer jacket, a core positioned concentrically in spaced relationship within the outer jacket and a reinforcing cage positioned between the center core and the jacket and sealing means are provided for sealing the relationship between the bottom pallet, the outer jacket and the inner core. Use is made of movable elastic seals on the lower ends of the outer jacket and the core. The seals can be expanded inwardly toward the pallet by means of a positive pressure until the concrete has been poured into the form and compacted by vibration. Negative pressure is then utilized to withdraw the elastic seals from the formed pipe and the inner core and outer jacket are subsequently removed from the green pipe.
    Type: Grant
    Filed: September 9, 1977
    Date of Patent: October 31, 1978
    Inventor: Carl R. Joelson
  • Patent number: 4101622
    Abstract: A pipe mold for vertically cast concrete pipe includes a cylindrical outer mold case, a cylindrical core spaced inside the mold case, and a pipe-reinforcing cylinder between the core and the case. A system for casting concrete in the pipe mold includes a flat facing ring above the annular space between the mold case and the cylinder. A chute assembly mounted concentrically above the pipe mold includes several radially extending and spaced apart pouring chutes extending downwardly from the center of the chute assembly to corresponding circumferentially spaced apart openings in the facing ring. The pouring chutes channel the flow of concrete into the openings in the facing ring to fill the pipe mold to the bottom surface of the facing ring, which forms a flat annular end section at the desired elevation on the pipe. The facing ring eliminates the need for hand finishing and measuring which is common in the prior art manufacture of vertically cast concrete pipe.
    Type: Grant
    Filed: December 30, 1975
    Date of Patent: July 18, 1978
    Assignee: Ameron, Inc.
    Inventors: Frank M. Wells, Gordon J. Black
  • Patent number: 4047693
    Abstract: A supporting ring for casting machines for concrete pipes for use in moulding the socket end of the pipe and as a base for the green pipe during the removal of the casting mould and the initial hardening of the concrete, said ring consisting of a hollow annular body of a closed, preferably substantially rectangular cross-section.
    Type: Grant
    Filed: January 12, 1976
    Date of Patent: September 13, 1977
    Assignee: Pedershaab Maskinfabrik A/S
    Inventor: Bent Melchior Karlsen Holme
  • Patent number: 3945787
    Abstract: A cap rest assembly to support a closed bore cap slightly above the upper periphery of the pipe jacket in a packerhead/vibration system concrete pipe machine, which has a slump filler attachment enabling making of a green pipe including the upper end in a continuous operation by overfilling the jacket slightly, the cap rest assembly supporting and enabling automatic release of the closed bore cap when the slump filler compression ring depresses the closed bore cap and overfills concrete into the top end of the pipe jacket to complete the green pipe.
    Type: Grant
    Filed: April 19, 1973
    Date of Patent: March 23, 1976
    Assignee: Concrete Pipe Machinery Company
    Inventor: Ronald J. Walchek
  • Patent number: 3942936
    Abstract: A pipe mold for vertically cast concrete pipe includes a cylindrical outer mold case, a cylindrical core spaced inside the mold case, and a pipe-reinforcing cylinder between the core and the case. A system for casting concrete in the pipe mold includes a flat facing ring above the annular space between the mold case and the cylinder. A chute assembly mounted concentrically above the pipe mold includes several radially extending and spaced apart pouring chutes extending downwardly from the center of the chute assembly to corresponding circumferentially spaced apart openings in the facing ring. The pouring chutes channel the flow of concrete into the openings in the facing ring to fill the pipe mold to the bottom surface of the facing ring, which forms a flat annular end section at the desired elevation on the pipe. The facing ring eliminates the need for hand finishing and measuring which is common in the prior art manufacture of vertically cast concrete pipe.
    Type: Grant
    Filed: November 21, 1974
    Date of Patent: March 9, 1976
    Assignee: Ameron, Inc.
    Inventors: Frank M. Wells, Gordon J. Black
  • Patent number: 3941347
    Abstract: A composite pallet for forming the lower end of a concrete pipe cast in a vertical position includes a concrete base having an annular portion shaped to form the end of the pipe. An outer annular steel ring is bonded to the base around the outer periphery of the annular portion of the concrete base, and an inner annular steel ring is bonded to the base around the inner periphery of the annular portion. The two rings are more chip-resistant than the concrete base. The outer ring is shaped to receive one end of an outer cylindrical form, and the inner ring is shaped to receive one end of an inner cylindrical form so that an annular cavity is formed between the two cylindrical forms for casting the concrete pipe.
    Type: Grant
    Filed: November 6, 1974
    Date of Patent: March 2, 1976
    Assignee: Ameron, Inc.
    Inventors: Harry H. Robertson, Donnie H. Hicks, Hugh M. Hofmann