Patent US3577610A successfully refreshed from Google Patents.
US3577610A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for manufacturing prestressed concrete members
Assignee: Arthur D Little Inc
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Filing: 1968-04-16
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Granted: 1971-05-04
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Expires: 1988-04-16
Abstract
Abstract A system for casting prestressed concrete members on a highly automated, mass production basis. The system employs a plurality of portable molds, each of which defines a hollow mold cavity. The portable molds are preferably substantially identical in construction, include open top portions through which charges of concrete mixture can be directed into the mold cavities, and further include means for releasably securing lengths of reinforcing strand in a selected arrangement within each mold cavity. Conveying means carry a plurality of molds simultaneously along a predetermined path of travel through operating stations adapted to subject each mold to a series of successive operations. A mold cleaning and oiling station cleans the interior surfaces of each mold cavity and coats the interior surfaces with a releasing agent. An placement station inserts hardware into the mold cavities, to be cast within the concrete members. A strand placement station emplaces predetermined lengths of reinforcing strand within the mode cavities, and a tensioning station applies a selected pretensioning force to the reinforcing strand. Filling and compacting stations successively feed a measured charge of concrete mixture into each of the molds and compact the concrete charge in the molds. Means are provided to cure the concrete charge within each of the molds after the filling and compacting operations are completed. Conveyor means receive and convey a plurality of the molds simultaneously along a predetermined path of travel after the curing operation is completed. A tension releasing station operates to release the pretensioning load on the reinforcing strand emplaced within each of the molds. Means are provided downstream from the tension releasing station for preparing the molds for the removal of the cast concrete members. A demolding station operates to remove the cast concrete member from each mold. Means are also provided to finish the demolded concrete members and to prepare the empty molds for recirculation through the manufacturing system. In the preferred embodiment each operating station is provided with a portable mold, and the operating stations perform their respective operations substantially simultaneously, within a selected time interval.
Inventors
- 👤 Stanley V Margolin
- 👤 Paul W Glaser
- 👤 Leonard V Gallagher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:53
CPC Classifications
B; B28; B28B; B28B23/00; B28B23/02; B28B23/04; B28B23/06; B28B5/00; B28B5/02; B28B5/021; B28B5/022; B28B5/04; B28B7/00; B28B7/08
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
185 words
Apparatus for making prestressed concrete members comprising a plurality of hollow portable molds each defining a mold cavity and including gripping means to receive and releasably grip reinforcing strand placed within the mold cavity, conveyor means to move said molds along a predetermined path of travel successively through a plurality of operating stations positioned along said path, the stations including a mold cleaning station, a mold oiling station, a strand placement station to place reinforcing strand in a selected position within each mold cavity, a strand tensioning station to apply a selected external pretensioning load to said strand emplaced with each mold cavity, with said gripping means engaged with said strand to substantially maintain said external pretensioning load, a mold filling and compacting station, a tension releasing station including a releasing head engageable with said molds to disengage said gripping means from the associated strand and thereby release said external pretensioning load after the concrete in said mold cavity is cured, and a demolding station to discharge the cured concrete members from said molds after said external pretensioning load has been released from said strand.
Claim 2
Dependent Claim
185 words
Apparatus for making prestressed concrete members comprising a plurality of hollow portable molds each defining a mold cavity and including gripping means to receive and releasably grip reinforcing strand placed within the mold cavity, conveyor means to move said molds along a predetermined path of travel successively through a plurality of operating stations positioned along said path, the stations including a mold cleaning station, a mold oiling station, a strand placement station to place reinforcing strand in a selected position within each mold cavity, a strand tensioning station to apply a selected external pretensioning load to said strand emplaced with each mold cavity, with said gripping means engaged with said strand to substantially maintain said external pretensioning load, a mold filling and compacting station, a tension releasing station including a releasing head engageable with said molds to disengage said gripping means from the associated strand and thereby release said external pretensioning load after the concrete in said mold cavity is cured, and a demolding station to discharge the cured concrete members from said molds after said external pretensioning load has been released from said strand.
Claim 3
Dependent Claim
52 words
Molding apparatus in accordance with claim 2 including elevator means at each station to elevate said molds above said conveyor means during the operation of said stations, positioning means to orient said elevated molds into a selected position at each station, and means controlling said elevator means to operate said stations simultaneously.
Claim 4
Dependent Claim
45 words
The invention in accordance with claim 2 wherein said mold elevator positioned at said mold filling and compacting station includes vibrating means adapted to vibrate each of said molds as said mold is charged with said concrete mixture, and thereby facilitate the mold filling operation.
Claim 5
Dependent Claim
36 words
The molding apparatus in accordance with claim 4 wherein said tensioning station includes a tensioning head which applies a selected external pretensioning load to said strand by applying a measured tensioning force directly to said strand.
Claim 6
Dependent Claim
28 words
The molding apparatus in accordance with claim 1 wherein said tensioning station applies a selected pretensioning load to said strand by elongating said strand by a predetermined distance.
Claim 7
Dependent Claim
176 words
In a system for manufacturing prestressed concrete members, the combination comprising: a plurality of portable molds, each of which includes a hollow mold body defining a mold cavity for forming a prestressed concrete member and having an open portion through which said concrete member can be discharged from said mold cavity, each of said molds further including strand gripping means releasably engageable with reinforcing strand emplaced within said concrete member through which an external pretensioning load can be applied to said strand; means to support a plurality of said portable molds in longitudinally spaced relationship and operable to carry said filled molds along a selected path of Travel; and a tension releasing station to successively release the external pretensioning load on said strand after said strand is cast within each of said concrete members, said releasing station including a releasing head successively engageable with each of said molds at said releasing station to disengage said gripping means of each of said molds from the associated reinforcing strand to thereby release the external pretensioning load applied thereto.
Claim 8
Dependent Claim
176 words
In a system for manufacturing prestressed concrete members, the combination comprising: a plurality of portable molds, each of which includes a hollow mold body defining a mold cavity for forming a prestressed concrete member and having an open portion through which said concrete member can be discharged from said mold cavity, each of said molds further including strand gripping means releasably engageable with reinforcing strand emplaced within said concrete member through which an external pretensioning load can be applied to said strand; means to support a plurality of said portable molds in longitudinally spaced relationship and operable to carry said filled molds along a selected path of Travel; and a tension releasing station to successively release the external pretensioning load on said strand after said strand is cast within each of said concrete members, said releasing station including a releasing head successively engageable with each of said molds at said releasing station to disengage said gripping means of each of said molds from the associated reinforcing strand to thereby release the external pretensioning load applied thereto.
Claim 9
Dependent Claim
119 words
A system in accordance with claim 6 wherein each of said molds includes movable ends joined to said body and movable between an open position with respect to said body and a closed position engaged with said body; wherein said strand gripping means are positioned on said movable ends and operable to apply an external pretensioning force to the associated strand when said mold ends are in said closed position and to disengage the strand when the mold ends are in said open position; and further wherein said tension releasing head engages with and releases said gripping means and permits the removal of the strand from said gripping means by movement of said mold ends into said open position.
Claim 10
Dependent Claim
51 words
A system in accordance with claim 7 wherein said tension releasing head includes means to engage with and release said gripping means and means engageable with said mold ends to translate said mold ends from said closed position to said open position and thereby remove the strand from said gripping means.
Claim 11
Dependent Claim
185 words
In a system for manufacturing prestressed concrete members, the combination comprising: a mold body defining a hollow mold cavity; a mold end assembly movable between a closed position engaged with said mold body and an opened position spaced from said body; said end assembly including an end plate engageable with said body, a chuck plate aligned with and movable with respect to said end plate, strand gripping means on said chuck plate, grip releasing means, and locking means positioned between said end and chuck plates and operable to maintain a pretensioning load in strand engaged by said gripping means by spacing said chuck plate a predetermined distance from said end plate; and a releasing head for selectively releasing the strand pretensioning load; said releasing head comprising force-applying means engageable with said end and chuck plates to separate said plates and release said locking means; means to engage said strand gripping means with said grip releasing means to deactivate said gripping means; and means to translate said end assembly from said closed position to said opened position to disengage said gripping means from the reinforcing strand.
Claim 12
Dependent Claim
185 words
In a system for manufacturing prestressed concrete members, the combination comprising: a mold body defining a hollow mold cavity; a mold end assembly movable between a closed position engaged with said mold body and an opened position spaced from said body; said end assembly including an end plate engageable with said body, a chuck plate aligned with and movable with respect to said end plate, strand gripping means on said chuck plate, grip releasing means, and locking means positioned between said end and chuck plates and operable to maintain a pretensioning load in strand engaged by said gripping means by spacing said chuck plate a predetermined distance from said end plate; and a releasing head for selectively releasing the strand pretensioning load; said releasing head comprising force-applying means engageable with said end and chuck plates to separate said plates and release said locking means; means to engage said strand gripping means with said grip releasing means to deactivate said gripping means; and means to translate said end assembly from said closed position to said opened position to disengage said gripping means from the reinforcing strand.
Claim 13
Dependent Claim
406 words
In a system for manufacturing prestressed concrete members, the combination comprising: a plurality of molds each including a mold body defining a hollow mold cavity having an opened top portion and movable mold ends slidably connected to said mold body; strand gripping means on said mold ends to releasably grip reinforcing strand and apply an external pretensioning force thereto; first conveyor means to carry said molds along a selected path of travel; a tension releasing station positioned adjacent said first conveyor, said releasing station including a releasing head positioned above said first conveyor and operably engageable with the movable mold ends to successively disengage said gripping means from the free ends of the associated reinforcing strand, thereby releasing the external pretensioning load applied to the strand, and to translate said movable mold ends outwardly into an open position with respect to the body of the associated mold beyond the length of said free ends of said strand; mold elevator means to receive said molds as said molds are carried to said releasing station by said first conveyor and operable to successively engage said molds with said releasing head; positioning means at said tension releasing station to orient said molds into a selected position with respect to said releasing head; sEcond conveyor means positioned downstream from said tension releasing station engageable with said opened mold ends to support a plurality of said molds and the associated concrete members cast therein; means to successively transfer each of said molds from said first conveyor to said second conveyor in an inverted position; supporting means extending along said second conveyor for a selected distance to support the concrete members within said inverted molds as said molds are carried by said second conveyor; a demolding station positioned along the path of said second conveyor to successively discharge the concrete members from said inverted molds, said demolding station including a platform movable into alignment with said supporting means to successively receive and support concrete members as the associated inverted mold becomes positioned at said demolding station, said platform being further movable to successively lower said concrete members between the opened movable ends of the associated mold; means positioned adjacent said demolding station to receive and support said demolded members; and a finishing station to successively finish each of said demolded concrete members, said finishing station including cutting means to sever the projecting free ends of reinforcing strand from each of said members.
Claim 14
Dependent Claim
406 words
In a system for manufacturing prestressed concrete members, the combination comprising: a plurality of molds each including a mold body defining a hollow mold cavity having an opened top portion and movable mold ends slidably connected to said mold body; strand gripping means on said mold ends to releasably grip reinforcing strand and apply an external pretensioning force thereto; first conveyor means to carry said molds along a selected path of travel; a tension releasing station positioned adjacent said first conveyor, said releasing station including a releasing head positioned above said first conveyor and operably engageable with the movable mold ends to successively disengage said gripping means from the free ends of the associated reinforcing strand, thereby releasing the external pretensioning load applied to the strand, and to translate said movable mold ends outwardly into an open position with respect to the body of the associated mold beyond the length of said free ends of said strand; mold elevator means to receive said molds as said molds are carried to said releasing station by said first conveyor and operable to successively engage said molds with said releasing head; positioning means at said tension releasing station to orient said molds into a selected position with respect to said releasing head; sEcond conveyor means positioned downstream from said tension releasing station engageable with said opened mold ends to support a plurality of said molds and the associated concrete members cast therein; means to successively transfer each of said molds from said first conveyor to said second conveyor in an inverted position; supporting means extending along said second conveyor for a selected distance to support the concrete members within said inverted molds as said molds are carried by said second conveyor; a demolding station positioned along the path of said second conveyor to successively discharge the concrete members from said inverted molds, said demolding station including a platform movable into alignment with said supporting means to successively receive and support concrete members as the associated inverted mold becomes positioned at said demolding station, said platform being further movable to successively lower said concrete members between the opened movable ends of the associated mold; means positioned adjacent said demolding station to receive and support said demolded members; and a finishing station to successively finish each of said demolded concrete members, said finishing station including cutting means to sever the projecting free ends of reinforcing strand from each of said members.
Claim 15
Dependent Claim
56 words
The invention in accordance with claim 1 wherein said mold cleaning and oiling stations include a collection head to collect and remove the dust and debris loosened from each of said mold cavities and an oiling head to apply a coat of releasing agent to the cleaned interior wall portions of each of said mold cavities.
Claim 16
Dependent Claim
52 words
The invention in accordance with claim 1 wherein said mold filling and compacting station includes a filling head formed to store a measured volume of concrete mixture in a distribution pattern which substantially coincides with the predetermined distribution pattern for said concrete mixture within the cavity of each of said portable molds.
Claim 17
Dependent Claim
380 words
In a system for manufacturing prestressed concrete members, the combination comprising; a plurality of portable molds, each of which includes a hollow mold body defining a mold cavity filled with a cured prestressed concrete member and having an open portion through which said cured concrete member can be discharged from said mold cavity, each of said molds further including strand gripping means releasably engaged with reinforcing strand cast within said cured concrete member through which an external pretensioning load is applied to said strand; means adapted to support a plurality of said filled portable molds in a longitudinally spaced relationship and operable to carry said filled molds along a selected path of travel; a tension releasing station to successively release said external pretensioning load on said strand cast within each of said concrete members, said releasing station including a releasing head successively engageable with each of said molds at said releasing station and further being operable to disengage said gripping means of each of said molds from the associated reinforcing strand to thereby release the external pretensioning load applied thereto; means positioned adjacent said tension releasing station to successively receive said filled molds and engage said molds with said releasing head; positioning means arranged at said tension releasing station to engage with and orient said molds into a selected position with respect to said releasing head; support means positioned downstream from said tension releasing station to support a plurality of said filled molds in a longitudinally spaced relationship with said gripping means disengaged from said reinforcing strand; a demolding station to successively discharge said cured concrete member from each of said filled molds, said demolding station including positioning means engageable with each of said molds and the associated concrete member to maintain said molds and Concrete members in selected positions at said demolding station; demolding means successively engageable with each of said cured concrete members as each of said filled molds is successively carried to said demolding station to separate said cured concrete member from the mold positioned at said demolding station, to thereby discharge said members from said molds; and member-supporting means positioned adjacent said demolding means at said demolding station to receive each of said cured concrete members after said members are discharged from the associated portable mold.
Claim 18
Dependent Claim
380 words
In a system for manufacturing prestressed concrete members, the combination comprising; a plurality of portable molds, each of which includes a hollow mold body defining a mold cavity filled with a cured prestressed concrete member and having an open portion through which said cured concrete member can be discharged from said mold cavity, each of said molds further including strand gripping means releasably engaged with reinforcing strand cast within said cured concrete member through which an external pretensioning load is applied to said strand; means adapted to support a plurality of said filled portable molds in a longitudinally spaced relationship and operable to carry said filled molds along a selected path of travel; a tension releasing station to successively release said external pretensioning load on said strand cast within each of said concrete members, said releasing station including a releasing head successively engageable with each of said molds at said releasing station and further being operable to disengage said gripping means of each of said molds from the associated reinforcing strand to thereby release the external pretensioning load applied thereto; means positioned adjacent said tension releasing station to successively receive said filled molds and engage said molds with said releasing head; positioning means arranged at said tension releasing station to engage with and orient said molds into a selected position with respect to said releasing head; support means positioned downstream from said tension releasing station to support a plurality of said filled molds in a longitudinally spaced relationship with said gripping means disengaged from said reinforcing strand; a demolding station to successively discharge said cured concrete member from each of said filled molds, said demolding station including positioning means engageable with each of said molds and the associated concrete member to maintain said molds and Concrete members in selected positions at said demolding station; demolding means successively engageable with each of said cured concrete members as each of said filled molds is successively carried to said demolding station to separate said cured concrete member from the mold positioned at said demolding station, to thereby discharge said members from said molds; and member-supporting means positioned adjacent said demolding means at said demolding station to receive each of said cured concrete members after said members are discharged from the associated portable mold.
Claim 19
Dependent Claim
109 words
The invention in accordance with claim 13 wherein said demolding means comprises an elevator mechanism positioned at said demolding station and wherein said member-supporting means comprises a conveyor positioned adjacent said elevator mechanism, said elevator mechanism including a platform movable into alignment with said support means to engage with the cured concrete member associated with a mold as said mold becomes positioned at said demolding station, said elevator platform being further movable to transfer a cured concrete member to said conveyor, so that the controlled movement of said elevator platform removes the concrete member engaged with said platform from the associated mold and transfers said member to said conveyor.
Claim 20
Dependent Claim
55 words
The invention in accordance with claim 14 wherein said system includes a finishing station positioned adjacent said conveyor to successively receive said cured concrete members demolded at said demolding station, said finishing station including strand cutting means to sever said strands from said cured concrete members as said members are carried through said finishing station.
Claim 21
Dependent Claim
96 words
The invention in accordance with claim 13 wherein said system includes mold turnover means positioned adjacent said support means downstream from said demolding station, said turnover means including a rotatable turnover head which is movable into alignment with said support means to successively receive empty molds from said demolding station, said turnover head being further rotatable into a position which inverts said empty molds received therein so that said empty molds are successively positioned with the open portions of said molds directed upwardly, whereby said turnover station orients said molds for recycling through said manufacturing system.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |