US20170247892A1 - Lifting anchor for precast concrete structures - Google Patents
Lifting anchor for precast concrete structures Download PDFInfo
- Publication number
- US20170247892A1 US20170247892A1 US15/444,387 US201715444387A US2017247892A1 US 20170247892 A1 US20170247892 A1 US 20170247892A1 US 201715444387 A US201715444387 A US 201715444387A US 2017247892 A1 US2017247892 A1 US 2017247892A1
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- pair
- legs
- concrete structure
- lifting
- undulations
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- 239000011178 precast concrete Substances 0.000 title claims abstract description 27
- 239000004567 concrete Substances 0.000 claims abstract description 45
- 239000002184 metal Substances 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims description 7
- 238000005266 casting Methods 0.000 claims description 2
- 239000011800 void material Substances 0.000 description 7
- 230000008901 benefit Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000011513 prestressed concrete Substances 0.000 description 2
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000009435 building construction Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G15/00—Forms or shutterings for making openings, cavities, slits, or channels
- E04G15/04—Cores for anchor holes or the like around anchors embedded in the concrete
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/18—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons
- E04B1/20—Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of concrete, e.g. reinforced concrete, or other stonelike material
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/14—Conveying or assembling building elements
- E04G21/142—Means in or on the elements for connecting same to handling apparatus
Definitions
- the present invention generally relates to lifting anchors for precast concrete structures, and more particularly to lifting anchors and assemblies for reinforced and/or prestressed concrete beams, girders, slabs, columns, panels, and the like.
- Precast concrete structures are often used in building constructions, and lifting anchors are commonly embedded or cast in the precast concrete structures to facilitate handling, since these structures can be difficult to hoist and position due to their weight, bulkiness, and susceptibility to damage, such as cracking, chipping, and other breakage.
- precompressed tensile zones of the structure can make the structure more susceptible to damage during handling and installation, such as when lifting anchors are ineffectively designed and/or located to cause interference with the prestressed strands embedded in the structure.
- the present invention provides a lifting anchor that is configured to be embedded in a precast concrete structure, such as a single-tee beam or double-tee slab or the like, that has pretensioned or prestressed strands forming a compressed zone or zones in the concrete structure.
- the lifting anchor includes a single strand or piece of metal bar stock that is bent to have a pair of elongated, parallel legs and a central section that integrally interconnects the legs and is used as the attachment point for connecting lifting chains or cables or the like.
- a lower end section of each of the legs includes undulations, such as waves, that are configured to engage the compressed zone in the concrete structure in a manner that provides a stable and secure lifting point and minimizes interference with the prestressed strands.
- the lifting anchor may be positioned to straddle opposing sides of the prestressed strands or to be disposed between spaced apart prestressed strands, thus allowing the lifting anchor to accommodate differently shaped and configured precast concrete structures in a manner that prevents interference with the prestressed strands.
- a lifting anchor is configured to be embedded in a precast concrete structure.
- the lifting anchor includes a single strand of metal bar stock that is bent to have a pair of elongated legs and a central section that integrally interconnects the pair of elongated legs.
- a lower end section of each of the pair of elongated legs includes undulations that are configured to engage in a compressed zone of a concrete structure resulting from prestressed strands cast in the concrete structure and configured to minimize interference with the prestressed strands.
- an apparatus includes a precast concrete structure that has a surface-forming panel portion, a panel-reinforcing rib portion, and prestressed strands disposed within the rib portion.
- a plurality of lifting anchors are positioned within the rib portion, where the plurality of lifting anchors each include a single strand of metal bar stock that has a pair of parallel legs and a leg-connecting section.
- a lower end section of each of the pair of parallel legs includes undulations shaped to engage in a compressed zone in the rib portion proximate the prestressed strands.
- a method for forming a concrete structure.
- the method includes providing a plurality of lifting anchors that each have a single strand of metal bar stock that includes a pair of parallel legs and a leg-connecting section, where a lower end section of the legs includes undulations bent into the single strand.
- Concrete is cast to form a precast concrete structure that includes a surface-forming panel portion, a panel-reinforcing rib portion, and prestressed strands that extend along a length of the rib portion.
- the plurality of lifting anchors Prior to hardening of the precast concrete structure, the plurality of lifting anchors are disposed within the rib portion with the undulations positioned to engage a compressed concrete zone in the precast concrete structure and to minimize interference with prestressed strands in the concrete structure.
- FIG. 1 is a cross-sectional view of a precast concrete structure having a lifting anchor with legs disposed between spaced apart arrangements of prestressed strands extending in the precast concrete structure to position waves formed at ends of the legs at a compressive zone formed by the prestressed strands, in accordance with the present invention
- FIG. 2 is a cross-sectional view of a precast concrete structure having an additional embodiment of a lifting anchor with legs disposed on opposing sides of prestressed strands extending in the precast concrete structure to position waves formed at ends of the legs at a compressive zone formed by the prestressed strands, in accordance with the present invention
- FIG. 3 is a side elevational view of the lifting anchor shown in FIG. 1 ;
- FIG. 4 is an additional side elevational view of the lifting anchor shown in FIG. 3 ;
- FIG. 5 is a perspective view of the lifting anchor shown in FIG. 3 ;
- FIG. 6 is another perspective view of the lifting anchor shown in FIG. 3 ;
- FIG. 7 is a top plan view of the lifting anchor shown in FIG. 3 ;
- FIG. 8 is a side elevational view of the lifting anchor shown in FIG. 2 ;
- FIG. 9 is an additional side elevational view of the lifting anchor shown in FIG. 8 ;
- FIG. 10 is a perspective view of the lifting anchor shown in FIG. 8 ;
- FIG. 11 is another perspective view of the lifting anchor shown in FIG. 8 ;
- FIG. 12 is a top plan view of the lifting anchor shown in FIG. 8 ;
- FIG. 13 is an upper perspective view of an additional embodiment of a lifting anchor having an attached void former
- FIG. 14 is a side elevational view of the lifting anchor shown in FIG. 13 ;
- FIG. 15 is an additional side elevational view of the lifting anchor shown in FIG. 13 ;
- FIG. 16 is a top plan view of the lifting anchor shown in FIG. 13 ;
- FIG. 17 is a bottom plan view of the lifting anchor shown in FIG. 13 .
- a lifting anchor 10 ( FIGS. 1 and 3-7 ), 110 ( FIGS. 2 and 8-12 ), 210 ( FIGS. 13-17 ) is configured to be cast or embedded in a precast concrete structure 40 , 140 , such as a single-tee beam ( FIGS. 1 and 2 ) or double-tee slab or the like.
- the precast concrete structure 40 , 140 has pretensioned or prestressed strands 42 , 142 that form a compressed zone or zones in the concrete structure 40 , 140 , which compress the concrete structure longitudinally along and in a direction generally parallel to the prestressed strands.
- the lifting anchor 10 , 110 is embedded in the precast concrete structure 40 , 140 at or near the compressed zone or zones to provide a secure anchor or attachment point for a lift chain or cable or the like, while also minimizing interference with the prestressed strands 42 , 142 . Further, the lifting anchor 10 , 110 may be configured to be positioned to either be disposed between spaced apart prestressed strands 42 ( FIG. 1 ) or to straddle opposing sides of closely arranged prestressed strands 142 ( FIG. 2 ), thus allowing the lifting anchor to accommodate differently shaped and configured precast concrete structures and pretensioning arrangements, within the functional requirements of particular structures.
- the concrete structures 40 , 140 are similarly shaped and include a surface-forming panel portion 44 , 144 and a panel-reinforcing rib portion 46 , 146 , where the prestressed strands 42 , 142 are disposed within and extend, parallel to each other, along a length of the rib portion 46 , 146 .
- the panel portion 44 , 144 is configured to be generally horizontally oriented, such as to form a base or support surface of a road, building, or parking structure or the like.
- the rib portion 46 , 146 extends along a lower section of the panel portion 44 , 144 to provide support and reinforcement to the panel portion 44 , 144 , thus increasing the load capacity of such a structure 40 , 140 .
- the prestressed strands 42 , 142 extend generally horizontally through the concrete structure 40 , 140 and are each disposed or spaced in two vertical arrangements or columns, with three strands spaced apart in a generally vertical stacked arrangement.
- the prestressed strands 42 , 142 in each concrete structure 40 , 140 form a compressed zone that generally surrounds the prestressed strands 42 , 142 in a lower section of the rib portion 46 , 146 .
- the strands 42 , 142 provide additional strength to the structure 40 , 140 by promoting compressive forces over tensile forces and provide stress distribution along the concrete structures 40 , 140 to help prevent flexural cracking and to counteract tension due to expected gravity loads, such as self-weight, superimposed dead loads, live loads, and the like. It is understood that the concrete structure in accordance with the present invention may be cast in various alternative shapes and pretensioning arrangements, such as with more or few strands and/or differently arranged strands.
- the lifting anchor 10 , 110 or strand lifter is embedded in the precast concrete structure 40 , 140 to facilitate lifting and handling of the structure 40 , 140 .
- the illustrated lifting anchor 10 , 110 is made from a single strand or piece of metal bar stock that is bent or otherwise formed to have a pair of elongated, parallel legs 12 , 112 and a central, leg-connecting section 14 , 114 that integrally interconnects the legs 12 , 112 and is used as an attachment point for connecting lifting chains or cables or the like.
- the single strand of metal bar stock that forms the illustrated lifting anchor 10 , 110 has a generally square cross-sectional shape.
- the lifting anchor in additional embodiments can be made from a single strand of bar stock of desired cross-sectional thickness and shape, such as round or rectangular or the like.
- the central section 14 , 114 includes an inverted V shape that is configured to be positioned as the uppermost portion of the lifting anchor 10 , 110 to be exposed by a void or cavity 48 , 148 or otherwise not embedded in the concrete structure 40 , 140 .
- the legs 12 , 112 are generally vertically arranged or disposed in the concrete structure to be generally perpendicular to the horizontally extending prestressed strands 42 , 142 .
- a lower end section 12 a , 112 a of each of the legs 12 , 112 includes undulations 16 , 116 that are configured to engage the compressed zone in the rib portion 46 , 146 of the concrete structure 40 , 140 in a manner that provides a stable and secure connection with the concrete structure 40 , 140 and minimizes interference with the prestressed strands 42 , 142 .
- the lifting anchor 10 can be positioned to extend between spaced apart prestressed strands 42 , such as shown in FIG. 1 , and the lifting anchor 110 can be positioned to straddle opposing sides of the prestressed strands 142 , such as shown in FIG. 2 .
- Multiple lifting anchors may be arranged along the concrete structure to provide multiple lifting points for the particular structure. It is conceivable that the lifting anchor in other embodiments may be arranged in different orientations, such as by lifting anchors engaging a single structure in alternating orientations along a length of the structure or by the lifting anchor accommodating differently shaped and configured precast concrete structures.
- the prestressed strands 42 are arranged with the two vertical arrangements or columns spaced apart laterally a sufficient distance to accommodate the legs 12 between the vertical arrangements of strands 42 .
- the central, leg-connecting section 14 and upper sections 12 b of the legs 12 extend generally in a common plane that extends longitudinally along the concrete structure 10 in substantial parallel alignment to the prestressed strands 42 .
- the undulations 16 at the lower end sections 12 a of the legs 12 are each provided as a wave shape that extends generally within the common plane defined by the legs 12 . Further, the undulations protrude laterally outward from a plane P 1 ( FIG.
- the planes P 1 defined separately by each of the legs 12 are generally perpendicular to the common plane extending between the legs 12 , such that the undulations 16 in the planes P 1 disperse the loads applied by using the lifting anchor 10 to the concrete structure vertically along the undulations 16 .
- the undulations 16 protrude away from the planes P 1 generally in the direction of the compressive forces in the concrete structure that are applied by the prestressed strands 42 , thereby minimizing interference with the prestressed strands 42 .
- the wave shape of the undulations 16 shown in FIGS. 1 and 3-7 include an amplitude defined between crests 16 a , 16 b ( FIG. 3 ) of the wave, where the interior crests 16 b are generally aligned with the plane P 1 defined at each of the legs 12 and the exterior crests 16 a extend from the plane P 1 a sufficient distance to provide a strong, secure, and minimally intrusive anchor point.
- the illustrated undulations 16 at the lower end sections 12 a of the elongated legs are substantially mirror images of each other, and both lower end sections 12 a of the legs 12 of the lifting anchor 10 are formed to provide waves that protrude laterally outwardly from each of the legs 12 . Again, as illustrated in FIG.
- the entire lifting anchor 10 extends generally within a common plane that is substantially parallel to the longitudinal direction of the strands 42 , positioning the undulations 16 to extend longitudinally within the concrete structure 40 . It is also contemplated that the undulations in additional embodiments of the lifting anchor may be differently shaped, such as with non-mirrored shapes and more or fewer wavelengths, such as a single wavelength or three wavelengths, among other conceivable shapes.
- the prestressed strands 142 are arranged with the two vertical arrangements or columns spaced closed together at a sufficient distance to allow the legs 112 to straddle opposing sides of the vertical arrangements of the prestressed strands 142 .
- the central, leg-connecting section 114 is shaped to separate the pair of parallel legs 112 away from each other at a spaced distance configured to dispose the legs 112 on opposing sides of the prestressed strands 142 .
- the common plane P 2 ( FIG. 9 ) that is defined by the central, leg-connecting section 114 and the upper sections 112 b of both of the legs 112 extends substantially perpendicular to the prestressed strands 142 .
- the lifting anchor 110 is formed from bending a single strand of generally square cross-sectional shaped bar stock to provide a central section 114 and a pair of elongated, parallel legs 112 that integrally extend from the central section 114 .
- the central upper sections 112 b of the legs 112 define a common plane P 2 , where the undulations 116 at the lower end sections 112 a of the legs 112 extend only from one side of the common plane P 2 .
- the undulations 116 at the lower end sections 112 a of legs 112 are bent to a wave shape generally equally on both side of legs 112 . As illustrated in FIGS.
- the plane P 2 extends generally perpendicularly to the strands 142 , such that and the waves extend in generally parallel alignment with the opposing vertical arrangements of strands 142 .
- the undulations 116 shown in FIGS. 9-12 are bent to a wave shape with wavelengths that extend two portions 16 a , 16 b (shown as crests of the wave) from each of the legs 112 , with one side of the crests 16 a generally aligned with the common plane P 2 .
- the undulations 116 protrude generally in the direction of the compressive forces in the concrete structure 140 that are applied by the prestressed strands 142 , thereby dispersing the loads applied by using the lifting anchor 110 to the concrete structure 140 vertically along the undulations 116 and minimizing interference with the prestressed strands 142 .
- an additional embodiment of a lifting anchor 210 is provided that has a generally round or circular cross-sectional shape, and further the central, leg-connecting section 214 and upper sections 212 b of the legs 212 extend generally in a common plane P 3 ( FIG. 14 ) that may extend substantially parallel or perpendicular to prestressed strands extending within a concrete structure.
- the undulations 216 at the lower end sections 212 a of the legs 212 are each provided as a wave shape that disperses the loads applied by using the lifting anchor 210 to the concrete structure vertically along the undulations 216 so as to prevent the load from being concentrated on a single strand and thereby minimizing interference with the prestressed strands.
- the wave shape of the undulations 216 are shown to include at least two wavelengths, where the wave shape of the undulations 216 have an amplitude defined between crests 216 a , 216 b ( FIG. 3 ) of the wave, which may be configured to be is less than a lateral spacing between two vertical arrangements or columns of the prestressed strands cast in a concrete structure. It is contemplated that the undulations may include more or fewer wavelengths, such as a single wavelength or three wavelengths, among other conceivable shapes.
- the undulations 216 at the lower end sections 212 a of the elongated legs 212 extend generally equally from both sides of the common plane P 3 , as defined by the central section 214 and upper sections 212 b of the legs 212 .
- both lower end sections 212 a of the legs 212 of the lifting anchor 210 are formed to provide waves that protrude from both sides of the common plane P 3 .
- the plane P 3 is arranged to extend generally parallel to the strands in a precast structure, the waves extend toward and perpendicular to the longitudinal direction of the strands.
- the undulations 216 shown in FIGS. 13-17 are bent or formed or cast to a wave shape with at least two wavelengths that extend two portions 216 a , 216 b (shown as crests of the wave) of each of the legs 212 from both sides of the common plane P 3 .
- the lifting anchor 210 has a recess-forming member or void former 218 engaged with the central section 214 of the lifting anchor 210 to conceal the central section 214 of the lifting anchor 210 .
- the void former 218 is removed to provide a cavity, such as shown as the cavities 48 , 148 in FIGS. 1 and 2 at the upper surface of the concrete structure 40 , 140 , to exposes the central section 214 of the anchor member 212 .
- the illustrated void former 218 includes openings that receive the outwardly-angled portions of the central section 214 to prevent intrusion of fluid concrete during the casting process.
- the void former 218 and lifting anchor 210 are configured to be disposed in the cast concrete, so that the central section 214 does not protrude above an outer flat surface of the concrete structure.
- Recess-forming members or void formers are generally known, such as provided in U.S. Design Pat. No. D559,499, which is hereby incorporated herein by reference in its entirety.
- the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in FIG. 1 .
- the invention may assume various alternative orientations, except where expressly specified to the contrary.
- the specific devices and processes illustrated in the attached drawings, and described in this specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.
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Abstract
Description
- The present application claims the filing benefit of U.S. Provisional Application Ser. No. 62/301,150, filed Feb. 29, 2016, which is hereby incorporated herein by reference in its entirety.
- The present invention generally relates to lifting anchors for precast concrete structures, and more particularly to lifting anchors and assemblies for reinforced and/or prestressed concrete beams, girders, slabs, columns, panels, and the like.
- Precast concrete structures are often used in building constructions, and lifting anchors are commonly embedded or cast in the precast concrete structures to facilitate handling, since these structures can be difficult to hoist and position due to their weight, bulkiness, and susceptibility to damage, such as cracking, chipping, and other breakage. With respect to prestressed concrete structures, precompressed tensile zones of the structure can make the structure more susceptible to damage during handling and installation, such as when lifting anchors are ineffectively designed and/or located to cause interference with the prestressed strands embedded in the structure.
- The present invention provides a lifting anchor that is configured to be embedded in a precast concrete structure, such as a single-tee beam or double-tee slab or the like, that has pretensioned or prestressed strands forming a compressed zone or zones in the concrete structure. The lifting anchor includes a single strand or piece of metal bar stock that is bent to have a pair of elongated, parallel legs and a central section that integrally interconnects the legs and is used as the attachment point for connecting lifting chains or cables or the like. A lower end section of each of the legs includes undulations, such as waves, that are configured to engage the compressed zone in the concrete structure in a manner that provides a stable and secure lifting point and minimizes interference with the prestressed strands. The lifting anchor may be positioned to straddle opposing sides of the prestressed strands or to be disposed between spaced apart prestressed strands, thus allowing the lifting anchor to accommodate differently shaped and configured precast concrete structures in a manner that prevents interference with the prestressed strands.
- According to one aspect of the present invention, a lifting anchor is configured to be embedded in a precast concrete structure. The lifting anchor includes a single strand of metal bar stock that is bent to have a pair of elongated legs and a central section that integrally interconnects the pair of elongated legs. A lower end section of each of the pair of elongated legs includes undulations that are configured to engage in a compressed zone of a concrete structure resulting from prestressed strands cast in the concrete structure and configured to minimize interference with the prestressed strands.
- According to another aspect of the present invention, an apparatus includes a precast concrete structure that has a surface-forming panel portion, a panel-reinforcing rib portion, and prestressed strands disposed within the rib portion. A plurality of lifting anchors are positioned within the rib portion, where the plurality of lifting anchors each include a single strand of metal bar stock that has a pair of parallel legs and a leg-connecting section. A lower end section of each of the pair of parallel legs includes undulations shaped to engage in a compressed zone in the rib portion proximate the prestressed strands.
- According to yet another aspect of the present invention, a method is provided for forming a concrete structure. The method includes providing a plurality of lifting anchors that each have a single strand of metal bar stock that includes a pair of parallel legs and a leg-connecting section, where a lower end section of the legs includes undulations bent into the single strand. Concrete is cast to form a precast concrete structure that includes a surface-forming panel portion, a panel-reinforcing rib portion, and prestressed strands that extend along a length of the rib portion. Prior to hardening of the precast concrete structure, the plurality of lifting anchors are disposed within the rib portion with the undulations positioned to engage a compressed concrete zone in the precast concrete structure and to minimize interference with prestressed strands in the concrete structure.
- These and other objects, advantages, purposes, and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.
-
FIG. 1 is a cross-sectional view of a precast concrete structure having a lifting anchor with legs disposed between spaced apart arrangements of prestressed strands extending in the precast concrete structure to position waves formed at ends of the legs at a compressive zone formed by the prestressed strands, in accordance with the present invention; -
FIG. 2 is a cross-sectional view of a precast concrete structure having an additional embodiment of a lifting anchor with legs disposed on opposing sides of prestressed strands extending in the precast concrete structure to position waves formed at ends of the legs at a compressive zone formed by the prestressed strands, in accordance with the present invention; -
FIG. 3 is a side elevational view of the lifting anchor shown inFIG. 1 ; -
FIG. 4 is an additional side elevational view of the lifting anchor shown inFIG. 3 ; -
FIG. 5 is a perspective view of the lifting anchor shown inFIG. 3 ; -
FIG. 6 is another perspective view of the lifting anchor shown inFIG. 3 ; -
FIG. 7 is a top plan view of the lifting anchor shown inFIG. 3 ; -
FIG. 8 is a side elevational view of the lifting anchor shown inFIG. 2 ; -
FIG. 9 is an additional side elevational view of the lifting anchor shown inFIG. 8 ; -
FIG. 10 is a perspective view of the lifting anchor shown inFIG. 8 ; -
FIG. 11 is another perspective view of the lifting anchor shown inFIG. 8 ; -
FIG. 12 is a top plan view of the lifting anchor shown inFIG. 8 ; -
FIG. 13 is an upper perspective view of an additional embodiment of a lifting anchor having an attached void former; -
FIG. 14 is a side elevational view of the lifting anchor shown inFIG. 13 ; -
FIG. 15 is an additional side elevational view of the lifting anchor shown inFIG. 13 ; -
FIG. 16 is a top plan view of the lifting anchor shown inFIG. 13 ; and -
FIG. 17 is a bottom plan view of the lifting anchor shown inFIG. 13 . - Referring now to the drawings and the illustrative embodiments depicted therein, a lifting anchor 10 (
FIGS. 1 and 3-7 ), 110 (FIGS. 2 and 8-12 ), 210 (FIGS. 13-17 ) is configured to be cast or embedded in aprecast concrete structure FIGS. 1 and 2 ) or double-tee slab or the like. Theprecast concrete structure prestressed strands concrete structure lifting anchor precast concrete structure prestressed strands lifting anchor FIG. 1 ) or to straddle opposing sides of closely arranged prestressed strands 142 (FIG. 2 ), thus allowing the lifting anchor to accommodate differently shaped and configured precast concrete structures and pretensioning arrangements, within the functional requirements of particular structures. - As shown in
FIGS. 1 and 2 , theconcrete structures panel portion rib portion prestressed strands rib portion panel portion rib portion panel portion panel portion structure - As also illustrated in
FIGS. 1 and 2 , theprestressed strands concrete structure prestressed strands concrete structure prestressed strands rib portion strands structure concrete structures - With further reference to
FIGS. 1 and 2 , thelifting anchor precast concrete structure structure lifting anchor parallel legs section legs lifting anchor central section lifting anchor cavity concrete structure legs prestressed strands lower end section legs undulations rib portion concrete structure concrete structure prestressed strands - The lifting
anchor 10 can be positioned to extend between spaced apartprestressed strands 42, such as shown inFIG. 1 , and thelifting anchor 110 can be positioned to straddle opposing sides of theprestressed strands 142, such as shown inFIG. 2 . Multiple lifting anchors may be arranged along the concrete structure to provide multiple lifting points for the particular structure. It is conceivable that the lifting anchor in other embodiments may be arranged in different orientations, such as by lifting anchors engaging a single structure in alternating orientations along a length of the structure or by the lifting anchor accommodating differently shaped and configured precast concrete structures. - With reference to the
lifting anchor 10 shown inFIGS. 1 and 3-7 , theprestressed strands 42 are arranged with the two vertical arrangements or columns spaced apart laterally a sufficient distance to accommodate thelegs 12 between the vertical arrangements ofstrands 42. The central, leg-connectingsection 14 andupper sections 12 b of thelegs 12 extend generally in a common plane that extends longitudinally along theconcrete structure 10 in substantial parallel alignment to theprestressed strands 42. Theundulations 16 at thelower end sections 12 a of thelegs 12 are each provided as a wave shape that extends generally within the common plane defined by thelegs 12. Further, the undulations protrude laterally outward from a plane P1 (FIG. 3 ) defined by a linear extension of each of theupper sections 12 b of thelegs 12. Thus, the planes P1 defined separately by each of thelegs 12 are generally perpendicular to the common plane extending between thelegs 12, such that theundulations 16 in the planes P1 disperse the loads applied by using the liftinganchor 10 to the concrete structure vertically along theundulations 16. As such, theundulations 16 protrude away from the planes P1 generally in the direction of the compressive forces in the concrete structure that are applied by theprestressed strands 42, thereby minimizing interference with theprestressed strands 42. - The wave shape of the
undulations 16 shown inFIGS. 1 and 3-7 include an amplitude defined betweencrests 16 a, 16 b (FIG. 3 ) of the wave, where the interior crests 16 b are generally aligned with the plane P1 defined at each of thelegs 12 and the exterior crests 16 a extend from the plane P1 a sufficient distance to provide a strong, secure, and minimally intrusive anchor point. Further, the illustratedundulations 16 at thelower end sections 12 a of the elongated legs are substantially mirror images of each other, and bothlower end sections 12 a of thelegs 12 of the liftinganchor 10 are formed to provide waves that protrude laterally outwardly from each of thelegs 12. Again, as illustrated inFIG. 1 , theentire lifting anchor 10 extends generally within a common plane that is substantially parallel to the longitudinal direction of thestrands 42, positioning theundulations 16 to extend longitudinally within theconcrete structure 40. It is also contemplated that the undulations in additional embodiments of the lifting anchor may be differently shaped, such as with non-mirrored shapes and more or fewer wavelengths, such as a single wavelength or three wavelengths, among other conceivable shapes. - In an additional embodiment, as shown in
FIGS. 2 and 8-12 , theprestressed strands 142 are arranged with the two vertical arrangements or columns spaced closed together at a sufficient distance to allow thelegs 112 to straddle opposing sides of the vertical arrangements of theprestressed strands 142. As such, the central, leg-connectingsection 114 is shaped to separate the pair ofparallel legs 112 away from each other at a spaced distance configured to dispose thelegs 112 on opposing sides of theprestressed strands 142. Thus, the common plane P2 (FIG. 9 ) that is defined by the central, leg-connectingsection 114 and theupper sections 112 b of both of thelegs 112 extends substantially perpendicular to theprestressed strands 142. - With reference to
FIGS. 2 and 8-12 , the liftinganchor 110 is formed from bending a single strand of generally square cross-sectional shaped bar stock to provide acentral section 114 and a pair of elongated,parallel legs 112 that integrally extend from thecentral section 114. As shown inFIG. 9 , the centralupper sections 112 b of thelegs 112 define a common plane P2, where theundulations 116 at thelower end sections 112 a of thelegs 112 extend only from one side of the common plane P2. Theundulations 116 at thelower end sections 112 a oflegs 112 are bent to a wave shape generally equally on both side oflegs 112. As illustrated inFIGS. 2 and 9 , the plane P2 extends generally perpendicularly to thestrands 142, such that and the waves extend in generally parallel alignment with the opposing vertical arrangements ofstrands 142. Theundulations 116 shown inFIGS. 9-12 are bent to a wave shape with wavelengths that extend twoportions 16 a, 16 b (shown as crests of the wave) from each of thelegs 112, with one side of the crests 16 a generally aligned with the common plane P2. Thus, as shown inFIG. 2 , theundulations 116 protrude generally in the direction of the compressive forces in theconcrete structure 140 that are applied by theprestressed strands 142, thereby dispersing the loads applied by using thelifting anchor 110 to theconcrete structure 140 vertically along theundulations 116 and minimizing interference with theprestressed strands 142. - As shown in
FIGS. 13-17 , an additional embodiment of alifting anchor 210 is provided that has a generally round or circular cross-sectional shape, and further the central, leg-connectingsection 214 andupper sections 212 b of thelegs 212 extend generally in a common plane P3 (FIG. 14 ) that may extend substantially parallel or perpendicular to prestressed strands extending within a concrete structure. Theundulations 216 at thelower end sections 212 a of thelegs 212 are each provided as a wave shape that disperses the loads applied by using thelifting anchor 210 to the concrete structure vertically along theundulations 216 so as to prevent the load from being concentrated on a single strand and thereby minimizing interference with the prestressed strands. The wave shape of theundulations 216 are shown to include at least two wavelengths, where the wave shape of theundulations 216 have an amplitude defined betweencrests 216 a, 216 b (FIG. 3 ) of the wave, which may be configured to be is less than a lateral spacing between two vertical arrangements or columns of the prestressed strands cast in a concrete structure. It is contemplated that the undulations may include more or fewer wavelengths, such as a single wavelength or three wavelengths, among other conceivable shapes. - As shown in
FIG. 14 , theundulations 216 at thelower end sections 212 a of theelongated legs 212 extend generally equally from both sides of the common plane P3, as defined by thecentral section 214 andupper sections 212 b of thelegs 212. Thus, bothlower end sections 212 a of thelegs 212 of thelifting anchor 210 are formed to provide waves that protrude from both sides of the common plane P3. When the plane P3 is arranged to extend generally parallel to the strands in a precast structure, the waves extend toward and perpendicular to the longitudinal direction of the strands. Theundulations 216 shown inFIGS. 13-17 are bent or formed or cast to a wave shape with at least two wavelengths that extend twoportions 216 a, 216 b (shown as crests of the wave) of each of thelegs 212 from both sides of the common plane P3. - As further shown in
FIGS. 13-17 , the liftinganchor 210 has a recess-forming member or void former 218 engaged with thecentral section 214 of thelifting anchor 210 to conceal thecentral section 214 of thelifting anchor 210. When the concrete structure cures and hardens (from wet/fluid concrete in the concrete form), the void former 218 is removed to provide a cavity, such as shown as thecavities FIGS. 1 and 2 at the upper surface of theconcrete structure central section 214 of theanchor member 212. The illustrated void former 218 includes openings that receive the outwardly-angled portions of thecentral section 214 to prevent intrusion of fluid concrete during the casting process. The void former 218 and liftinganchor 210 are configured to be disposed in the cast concrete, so that thecentral section 214 does not protrude above an outer flat surface of the concrete structure. Recess-forming members or void formers are generally known, such as provided in U.S. Design Pat. No. D559,499, which is hereby incorporated herein by reference in its entirety. - For purposes of this disclosure, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in
FIG. 1 . However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in this specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. - Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law. The disclosure has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described.
Claims (20)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US15/444,387 US20170247892A1 (en) | 2016-02-29 | 2017-02-28 | Lifting anchor for precast concrete structures |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US201662301150P | 2016-02-29 | 2016-02-29 | |
US15/444,387 US20170247892A1 (en) | 2016-02-29 | 2017-02-28 | Lifting anchor for precast concrete structures |
Publications (1)
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US20170247892A1 true US20170247892A1 (en) | 2017-08-31 |
Family
ID=59679413
Family Applications (1)
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US15/444,387 Abandoned US20170247892A1 (en) | 2016-02-29 | 2017-02-28 | Lifting anchor for precast concrete structures |
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US (1) | US20170247892A1 (en) |
CA (1) | CA2959370A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20200149302A1 (en) * | 2017-08-23 | 2020-05-14 | Midwest Concrete & Masonry Supply, Inc. | Lifting anchor assembly for precast concrete structures |
US10774523B2 (en) * | 2018-02-08 | 2020-09-15 | Reubart Enterprises, LLC | Brace insert device used in the construction of concrete panels |
EP3879046A1 (en) * | 2020-03-13 | 2021-09-15 | Kp1 | Lifting device for construction element, corresponding construction element and manufacturing method |
USD1010160S1 (en) * | 2021-07-14 | 2024-01-02 | Illinois Tool Works Inc. | Anchor |
USD1022259S1 (en) * | 2021-06-07 | 2024-04-09 | Illinois Tool Works Inc. | Anchor |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3160988A (en) * | 1960-12-16 | 1964-12-15 | Chester I Williams | Stress-gradient anchor |
US8695287B1 (en) * | 2012-06-27 | 2014-04-15 | Sidney E. Francies, III | Precast pre-stressed concrete tee lift anchor |
-
2017
- 2017-02-28 CA CA2959370A patent/CA2959370A1/en not_active Abandoned
- 2017-02-28 US US15/444,387 patent/US20170247892A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3160988A (en) * | 1960-12-16 | 1964-12-15 | Chester I Williams | Stress-gradient anchor |
US8695287B1 (en) * | 2012-06-27 | 2014-04-15 | Sidney E. Francies, III | Precast pre-stressed concrete tee lift anchor |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20200149302A1 (en) * | 2017-08-23 | 2020-05-14 | Midwest Concrete & Masonry Supply, Inc. | Lifting anchor assembly for precast concrete structures |
US10837185B2 (en) * | 2017-08-23 | 2020-11-17 | Midwest Concrete & Masonry Supply, Inc. | Lifting anchor assembly for precast concrete structures |
US10774523B2 (en) * | 2018-02-08 | 2020-09-15 | Reubart Enterprises, LLC | Brace insert device used in the construction of concrete panels |
EP3879046A1 (en) * | 2020-03-13 | 2021-09-15 | Kp1 | Lifting device for construction element, corresponding construction element and manufacturing method |
FR3108129A1 (en) * | 2020-03-13 | 2021-09-17 | Kp1 | Lifting device for construction element, construction element and manufacturing method thereof |
USD1022259S1 (en) * | 2021-06-07 | 2024-04-09 | Illinois Tool Works Inc. | Anchor |
USD1010160S1 (en) * | 2021-07-14 | 2024-01-02 | Illinois Tool Works Inc. | Anchor |
Also Published As
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CA2959370A1 (en) | 2017-08-29 |
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