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US 4,836,762 AGranted
Apparatus for molding concrete blocks or bricks
OwnerLindsey B. Davis, Jr.inventor
Life of this patent
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OwnerLindsey B. Davis, Jr.inventor
Estimating the term…
Concrete elements, such as blocks or bricks, are molded or cast by forming in a primary mold cavity a secondary mold made of a portion of a thermoplastic film which has been contacted with a flat heater surface to assure a uniformly heated film portion which is then sucked into the primary mold cavity without wrinkles and filled with concrete mix. The secondary mold with the concrete mix in it is withdrawn, for example, sucked out of the primary mold cavity well before any effective hardening of the concrete mix, so that curing and hardening takes place in the secondary mold outside the primary mold cavity. This early withdrawing is important because it avoids expansion of the curing mix in the primary mold, whereby removal from the primary mold is facilitated. Additionally, the early removal with the aid of the secondary mold assures a more efficient use of the primary molds which are used again while the hardening is still going on in the secondary mold. The apparatus for performing the method includes a turntable and a stepwise drive for sequentially stepping the turntable carrying a plurality of primary molds into cooperation with several work stations which are so controlled that the early withdrawal of the filled secondary mold from the primary mold cavity is assured.
An apparatus for automatically casting concrete elements, comprising a plurality of primary mold cavities, means for carrying said plurality of primary mold cavities having open mold tops and drive means operatively connected to said carrying means for stepping said carrying means in a timed sequence into cooperation with a plurality of operating stations comprising a first main station including a solid heating device having a flat surface for contacting and uniformly heating a thermoplastic film portion located on said open mold top, said flat surface having an area corresponding at least to the surface area of said open mold top for closing said open mold top when a thermoplastic film portion is being heated, means for evacuating air from said primary mold cavities to pull a heated thermoplastic film portion into said primary mold cavity, for forming a secondary mold in said primary mold cavity, means for removing said heating device from said primary mold cavity thereby opening said secondary mold, a second main station including means for filling concrete mix into said open secondary mold inside said primary mold cavity, a third main station including means for removing a filled secondary mold from a primary mold cavity, and means for controlling said stepping drive means to provide a dwell time for each of said stations such that said removing of a filled secondary mold takes place prior to any substantially noticeable or effective hardening of said concrete mix, and wherein said means for removing a filled secondary mold from a primary mold cavity comprise a rigid suction pipe connectable to a source of reduced pressure, means connected to said rigid suction pipe for moving said suction pipe back and forth between a secondary mold pick-up position and a secondary mold discharge position, lifting plate means connected to a lower end of said rigid suction pipe for contacting a rim of said secondary mold to engage said secondary mold rim in a suction tight manner, and means for controlling an application of reduced pressure through said suction pipe and through said lifting plate means for holding said secondary mold with its content to said lifting plate means when said secondary mold with its content is removed out of the respective primary mold cavity.
An apparatus for automatically casting concrete elements, comprising means for carrying a plurality of primary mold cavities having open mold tops and drive means operatively connected to said carrying means for stepping said carrying means in a timed sequence into cooperation with a plurality of operating stations comprising a first main station including a solid heating device having a flat surface for contacting and uniformly heating a thermoplastic film portion located on said open mold top, said flat surface having an area corresponding at least to the surface area of said open mold top for closing said open mold top when a thermoplastic film portion is being heated, means for evacuating air from said primary mold cavities to pull a heated thermoplastic film portion into said primary mold cavity for forming a secondary mold in said primary mold cavity, means for removing said heating device from said primary mold cavity thereby opening said secondary mold, a second main station including means for filling concrete mix into said open secondary mold inside said primary mold cavity, said second station including means for compacting said concrete mix, a third main station including means for removing a filled secondary mold from a primary mold cavity, and means for controlling said stepping drive means to provide a required dwell time for each of said stations such that said removing of a filled secondary mold takes place pior to any substantially noticeable or effective hardening of said concrete mix, wherein said means for filling comprise a dosing device including a dosing plate (105), said dosing plate being horizontally fixed relative to said compacting means, a filling box (115) slidably supported by said dosing plate, said filling box holding an excess volume of concrete mix, said dosing plate having an opening above an open mold cavity on said carrying means, said opening having a cross-sectional area corresponding approximately to that of said mold cavity, said dosing plate having such a thickness that a defined additional volume of concrete mix fits into said opening in said dosing plate, said excess volume of concrete mix being sufficient to fill said mold cavity and said additional volume in said dosing plate, so that said compacting means can compact said concrete mix for substantially completely filling said secondary mold with compacted concrete mix when compacting is completed.
Dependencies are inferred from the claim text.