CA1197989A - Handling system for precast units - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A small reinforced cavity is made in the precast unit and opens at the surface of the unit through a restricted slot.
An anchor member, having a transverse leg at its inner end, is inserted through the slot and rotated to 90° in secured position, so that the transverse leg will engage the surface of the cavity. The anchor member is firmly retained in secured position within the cavity. The outer end of the anchor member is either directly attached to a building structure for anchor-ing the precast unit in permanent position, or is fitted with a ring for use in hoisting and/or transporting the precast unit. The anchor member can be re-used. At least one safety pin is connected to the anchor member and is adapted to maintain the anchor member in its 90° secured rotated position. A com-pression spring surrounding the safety pin biases the latter into its locked position. The pin can therefore be retracted by forcibly acting against the bias of said spring.

Description

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The preoent inv0ntion relates to a h~ndling ~y~te~ for pr~csst unita, ~uch ~ reinforced pref~bricatsd concrete p~neln, ~nd the llke. The handling syot0m sarve~ both for hoi~ting and tr~n~-porting tha precast unitc and tor stt~ching the~ unlt~ tD ths etructure of a building or th~ like.
BACKGRO N~ Of THE INVENTION
Conventional syst3m~ for the handling of prefabricated unit~, su~h as rein~orced prefabricated concret~ panels, be3ms and the like, cons:lat of providing loop~ of steel cables smbsdded in tha lû concrat0 and ussd torthe hoi~ting tr~nsportation of the preca~t unit~.
Anchoring bolts or platas are al80 amb~dded in ths unit~ for uttaching the panals or baam~ to a bullding ~tructure. At the srection site, the loops of st~61 cable~ must b~ cut off and ths pocketc aurrounding these loop3 mu~t bs filled with mo~t~r or the like. The anchoring bolt~ o~
plstes Por ~ixing the pflnel~, for inst~nc~ building faclng panel~, do not p~rmit re,~oval of the fixed pansls ~ith~ut destroying the same.
Ther~fore, the~e panels cannot b~ removed, for ln~tsnca if ~n sddition to the building must bs effectsd.
Al30, the conuentional anchoring bolts snd platas form a rigid anchorag~ ~ystem which does not allow for contr~ction and expansiDn of the preca~t units undar tempersture changss, with tha rssult that th0~e unit~ often crack. Th~ ~nchorags aystHm al~o doas not allow for movHmant due to earthquak~s.

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It i~ th~refore ths gener~l objoct of the invention to prouide a handling 8y8tcm ~or precast unit~, which ov~rcomas thc abovs-noted dis~dvantaga~.
A more spacific objact of the inve~tion i8 to prouide-~uch a ~ystem in which the portion asaociatsd ~ith the precast units are us~d both ~or hoisting tha units during th~ir m~nipulation and trans-portation and ~or attaching tha unita to a building structure for ~lnal erection.
Anoth0r object o~ th0 present invHntion i8 to provida a

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119'79139 ~ystem of the charact~r deocribed, in which the ~nchor msmber~ aand for hoi~ting the preceat unit~ c~n be re-used.
Another object o~ the invention i8 ts provide ~ ~yat~m of the charact~r de~cribed, in which the prec~ot unit~, once attached to the building structure, can b0 detached without destroying the a~me, 80 that they may be re-u~ed.
Another object o~ the invention $~ to provide 8 syst~ of the character de3cribad, which a110WB co~emoRt of the att~ched unlts relative to the aupporting building ~tructure, ~o a~ to allow tor t~mp~rature-caused contr~ction and expansion and to bettar re~i~t to earthquak0s .
Still ~nothur object o~ ths invention is to provlde bardware for the purpose de3cribed, which i~ inexpensive and simple to ~a~utacture and which per~itu grsat ~aving~ with respect to the conventional ~ystem~
in tha handling ~nd attaching of the precast unlto.
SU~MARY OF THE INVENTION
The handling 8y8tem of the inventlon co~priees a r~inforced c~vity formsd in the preca~t unit and opening at an expo~ed facs thereof through a restricted slot. An anchor ma~ber, heving a transver~e 1~9 at it~ inner end, i8 inaertable throu~h the 810t and then rotated through ahout ona-qu~rter turn, ~o that thH lég engages th~ cavity transversely of tha 810t. Prefer~bly9 m~sn~ ~re provided to positively 0aint~in ths anchor me~ber in rotated cavity-eng~ging pOsitiOR. For hoi~ting and tran~porting the pracast units, the anchur mo~b~r i8 ~itted with a ring; for attaching th~ precast unit~ to a buildlng ~tructuro, the anchor memb~r ha~ a bent end sdapted to b~ directly ~ttachad to s~id building ~tructure.
Th~ ~oregoing will bscoma cIaarar by referring to tha ~nnexed drawinge~ in which:

BRIEF ~ESCRIPTIûN OF THE ORAWINGS
._ --Figur~ 1 i8 a ~ectional ~iew o~ a firat e~bodiment of the eyete~ of She lnvantion ueed to attach ~ preca~t unit to a bùilding ~tructur~, ~aid uiew being taken along lina 1-1 of Figure 2;

Figure 2 i.s a secti.on taken along line 2-2 of Figure l;
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Figure 3 is a sectionAl view of a second emboi iment used for hoisting and transpor-ting the precast unit, said view being taken along line 3-3 of Figure 4;
Eigure 4 is a section taken along line ~-4 ~f Eigl~e 3;
Figure 5 is a sect-onal view of a third embcdlment fox the hoisting and transporting of the precast unit and taken alc~ng line 5-5 of Figure 6;
Eigure 6 is a sec-tion taken along line 6-6 of Figure 5;
Figure 7 is a plcm view of the base plate and taken along line 7-7 of Figure 6;
Figures 8 to 13 are sectional views of tw~ different shapes of the reinforced cavities formed in the precast unit, together with various types of reinforcing rods associated therewith; and Eigures 14 to 19 are views of different shapes of anchoring n~m~er.

DETAILED DESCRIPTION O~' T~E PREF~RRED EMBODIMENTS
Figures 1 and 2 shc~w a precas-t ~it 1 which may be prefabricated reinforced concrete pane:L, a structural concrete beam or the like.
20 A pair of right angle short bars 2 are embedded .Ln the concrete and secured, as by welding, to reinfarcLng rcds 3. The right angle bars 2 are arranged in parallel relatianship with lateral wings extending in opposite direction wi-thin the concrete and with the other wings per-pendicuLar to the exposed surface of the precast uni~t l. A c~vity 4 is fo.rmed in the precast unit and is .ln communicatic~n ~ith.~he exterior ..
through a restricted slot as defined by the angle bars 2. Therefore, the slot is of elongated shape and the cavity 4 is wider than the slot as shc~n in Figure 1. The angle bars 2 are exposed within the slot and the cavity. An anchc)r member 5, in the form of a straight rod, is formed wi.th a bent outer end 6 and with an integral transverse leg 7 at its inn~r end. Said leg 7 forms a T-shape head with the ~hank of rod 5. The anchor m~mber 5 has a diameter slightly smaller than the width of ~le slot between the tw~ dngle bars 2, so that it may be inserted 7~
wlthin the cav.itv and -then the anchor member is rotated through substan-tially 90, so that the transverse leg 7 will extend transversely of the slot, as shown in Figures 1 and 2, to fasten the anchor member 5 to the precast unit 1. The rod ~, which is threaded, carries a nut 8, or collar~
together with plastic washer and a steel washer 9, which are applied tight aqainst the exposed surfc~ce of ~he unit 1 after the anchor bolt is in secured position. The collar 8 is preferably tack-welded to the anchor member 5.
Supposing the precast unit 1 is an external facing panel for a building, the bent end 6 of the anchor member 5 is simply welded to a steel beam 11, or to a metal plate (not shown) embedded in a concrete beam of the building structure.
In the case the panels are much longer than wide, which is the conventional format, the slot be-tween the angle bars is arranged to be vertically disposed, as shown, so as to allow ~mple relative movement in the vertical direction of the anchor member with respect to the panel 1 to compensate for temperature differentials between the panel 1, which is exposed to the exterior, and the supp~.ting st~ucture of beam 11. A
certain play also exists between ~nchor m~mber 5 and the angle bars 2 transversely of the latter.
The relative orientation of the T-shape head 7 and of the bent end 6 of anchor member 5 is such that the transverse head 7 will have to -take its rotated anchoring position w~en the bent end 6 is fixed to the beam 11, so as to prevent any mistake by the work;er at the erecting site.
Figures 14, 15, and 16, 17, re~pectivelyb show. two~di~ferent orientations of the bént end 6 of the anchor member with respect to the T-shape head 7 for fix.ing to a horizontal and to a vertic~l beam, respect-ively.
Instead of a T-shape head, the inn~r end of the anchor member 5 30. may form a single laterally-extending leg, as shown in Figures 12 and 13.
qhis is suitabl~ for panels or precast units a~ smaller dimensions cmd weight. In this case, only one angle bar 2 is provided, as shown in Fi~ures 8, 10, and 12, and the shape of the cavity 4 is as shcwn at 43' in these figures.

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,.~.' .!i I ~ _ 5 _ ~19'~19 figures ~ to 13 also show that thH reinforcing rods 3 n~y hav~ any convHntional shaps to be fir01y ambedded in th~ concret~.
Thase figures show also how the csvities 4 or 43'.
whether for a double-leg h~ad ar a single-leg head oP the anchoring members, are form~d ln the concrel~ during pouring. for thi~ pu~po3e7 onca the angle bare 2~ ~ith the reinforcing rods 3, have besn properly positioned in the molding form prior to concrete pouring, a block of polystyrene foam, as indicated at 43, is positioned bstween ths two angle bars 2, thl~ block havlng the ~h~pe of the cavity and of the communicating slot. The concrete ic tnOn poured and, once ~et, th0 block of polystyr~ne foam 43 i9 simply dissolved by using a proper snlvnn~, ~uch as methyl cl)loride, kurosenu or benzlna. As an alternatlve, -the polystyrene foam 43 can bn burnnd by applying suitabl~ heat. The ~3 block of polyatyrene foam mey be replaced by polyurethan0 foam.
Thu same reinforc~d cavlty just described for the precastunit l iB used for lifting and transporting ths units. A firat embodlment of the lifting and hoisting system i8 shown in figures 3 and 4.
~ hu lifting device is generally indicated at 12 and include~
a Rhort tubular member 13, of generally rectangular cro~s-section, hau-2~ ing bevalled Hnds 14 and 15 and defining a ba3e 16 and a top 17. 6ase 16 ie adapted to be eppliad flat egainqt tha sxposed face ~f tha concreta unlt 1. A safety pin 18 extend~ through aligned holss of the ~ase 16 and top 17, and i9 prouided with a head section 19 to which 18 secured a tranauerse grasping rod 20. Head 19 overlies top 17. A cnmpr~ssion spring 21 surrounds the safety pin 1~ intermedl~te the base 16 and top 17 and abuts at one end agaln3t a w~shsr 22 whioh 13 welded to ~afety pin 10 while the other end of compre~sion ~pring 21 abut~ again~t the inside of top 17. Thu~, the pln 10 i9 alw~y~ biased ~y ~prlng 21 to a position protruding from thu undar~ide of base 16.
~0 An anchor member 23, eguivalent to the anchor mamber 5 Of thu fir~t embodiment, axtunds through aligned hole~ of tubul~r membsr 13 and i9 walded or otherwis~ rlgidly sucursd to base 16 ~nd top 17. The nnd of anchor member ?3 hs~ an integral T-aheped haad 26, oimilar to ~l9t79~39 th0 r-shaped head ~ oF the first e~lt~odiment ard thi~ head la orient~d 90 a9 to extènd ut right angle to the plan~ c./rte~nlng the ea~ty pin la and anchor me~ber 23. Th_ ou~r ~ncl o~ th~ ~chor mKmber 23 ~lich protrudes from thH top 17 i8 thrnadad, as ~hown ~t 27, ~nd s~rewedinto a thrsaded bore of a hoisting ring 24.
To attach li~ting device 12 to th~ j3 eca~t unit 1, thw safety pln 15 i9 rdised by means of grasping rod 20,until lt~ lnn~r end i8 ~t least flush wltfl base 16 and the tubular member 13 i8 orl0nted trans-verse to the ~lot of caulty 4, ~o as to inssrt the ~-shapod hoAd 26 withln the slot and into the cavity 4. ThHn the ring 24i i3 rotated, togeth~r with tubular member 13, BO a8 to position the transvers0 leg of h~ad 26 acros~
the slot and, at the Hame time, the safety pin 18 becomHa ~ligned with the elot and i8 relea~ed to protrude within the slot. Therefore, ~a~ety pln lB prHvents acsldental rem~ al of tha llfting dHvice fro~ the precaat unit 1. The unit 1 may thu~ be hoisted and transported by a ~ultable hoisting cable attached to tha ring 24. The liPtlng dqvice 12 may be ea~ily detached from the precast unit und the anchor mHmber 5 used to attach the unit to a building ~tructure, a~ pr~vioualy deacrib~d.
Figure~ 5, 6, and 7 ~how another embodlment of a llfting ?0 and hoi~ting devic~ u~ad more particularly Yor heavier precaet unit~ and also when tilting of the unit i9 required during it~ handling. The lifting device is generally indicated at ? S and includes a base plate 29, which has a central holu 30 for alidably receiving thH anchoring mnmbnr 31. The base plats 29 hus dlamHtrically-oppobit~ notchea 32 in the central hole 30 to r'eceive diametrically-oppDsita lateral lugg 33 c~r-ried by the anchoring mHmber 31. Safety pins 34 are seCurad to and pro trude from the undur~ide of base plate 29 snd are adapted to engags the slot bet~een the ang~e bar~ 2.
An upper plate 35 1B welded,or otherwise rigidly aacured, to 3ù the base plate 29 on top of thu latter snd forms a sleevs 35~ fre01y surrounding th~ ~hank of the anchoring ~ember 31~ The upper end of ths sleeve 35~ 1B formsd by a flange 35ll for retaining on the slHeva 35~ a coller 36, which is frse to rotata about said sle~ve 35'.

A hniating ring 37 is pivoted on ietflral 3tuds fixed to collar 36 for pivotal mD~em0nt about an ~Xi9 trans~arse to that of tha ~hank of anchoring member 31 and, conaequantly~ to the exi~ o~ rotation of collar 36 about 31eeve 35~. Tharefora, ring 37 may pivot with ra0pect to the anchoring membsr 31 in ell planes through the universal joint for~sd by the collar 36 and the transvers0 pivotal stud3 ~7'.
The anchoring member 31 ha3 at its inner end o T-~haped head 3a, ~imilar to the T-~haped head 7 of the Yirst embodi~ent, whlch i8 adapted to be in~erted through the slot between the angls bars 2 and be rotated at right angla~ within the c~vity 4 to axtend tran~verflely of the slot in thn attached posltion to precast unit-l.
Rot~tion of the anchoring member 31 is facilitated by the pro~i~ion of the grasping rod 41 s0cured to the outer ancl of the anchoring member, as by welding or the like.
A~ ahown in figuras 6 and 7, the base plate 29 ha~ an annular undercut area 30' surrounding th~ central hole 30 for receiving lugs 33 and sllowing their rotation until they may enter notches 32. The depth of the undercut 30' is at lea3t equal to the vertical thicknass of the lugs 33.

,! Th~ outar snd of anchoring member 31 h~s a threaded portion 39 Por recHiving a nut 40 wh~oh ssrv~ to tighten the anchoring mambar 31 ~gain~t tha underface of angle bars 2 within the cavity 4.
To turther strength0n the attachment of the angl~ bars 2 to th~ reinforcing armatura o~ the precast unit 1, the angle bars 2 not only a~e ~e~ursd to the reinforcing rod~ 3 by welding, but additionsl U-shaped rein~orcing bars 42 have their wsb overlying the re~pactive angle bara 2 and thsir lege extending through holes ~ada in the laterfll wing3 of said angle bars 2, a9 shown in Figuras 5 and 6.
The dsvice of Flgur~s 5 to 7 i~ u~ed ~8 ~0110WR:

To attach the anchoring memb~r 31 to the prscaat unit, the n~ 40 is partly unscrawed from the tightanad position shcwn in Figure 6 to allow the lug~ 33 to eng~ga th~ undercut 30' of the ba3e plate 29 with the T-shaped he~d 3a oriented at right angles to th0 notch~s 3~. In this position, the T-head 38 iB at right angles to the po~itiwn ahown in Figure 6 . ~ _ ~ ~ ~t7 ~ ~ ~
and, ~herefore, -the T-shaped head 38 can be inserted through the slot of -the cavity 4 until the safety pins 34 engage this slot. The anchor-ing member 31 is then rotated to 90 by means of trasnsverse grasping rod 41. In this anchoring position, the lugs 33 are in register with the notches 32 and, -therefore, the nut 40 can be scre~ed ~ight against the flange 35'', thereby firmly applying the transverse legs of th~ T-shaped head 38 against the underside of th~ angle bars 2 within the cavity. In this final position, the lugs 33 engage the notches 32 which prevent accidental rotation of the anchoring m~mber with respect to the cavity 4. The precast unit can then be tilted and hoisted by ring 37 and transported without any rlsk of accidental disengagement of the lifting device from the precast unit.
To detach a lifting device 28 from the precast unit, it is only necessary to unscrew the nut 40, so that the lugs 33 will drop out of register with the notches 32 and then rotate the anchoring member 31 to align the T-shaped head 38 with the slot of the cavity, whereby the lifting device can be removed.
Figures 18 and 19 show two different orientations of the T-shaped head of the anchor m~mber 31.
As previously described, the cavity 4 and its associated slot is formed by using a shaped block 43, of foam plastic. However, the cavity can also be form~ by securing to the angle bars 2 a box of metal or plastic defining the surfaces of cavity 4 and the end s~rfaces of the slot and which is left in position after concxete pouring and setting.

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Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A handling system for a reinforced precast concrete element, such as a panel, beam and the like, comprising, in combination, such an element having an exposed surface rigid bar embedded in said element adjacent said exposed surface, an elongated slot opening at said surface and located adjacent said bar, said element having a cavity located inwardly of said bar and communicating with said slot, said cavity having a length at least equal to the length of said slot and a width greater than the width of said slot, said bar being exposed in said cavity and slot, an anchor member having a main straight leg and a transverse leg at its inner end, said main leg having a cross-sectional dimension to closely fit the width of said slot, said transverse leg having a length greater than the width of said slot and smaller than the width of said cavity, rotation of said anchoring member about the axis of said main leg to a rotated position about a quarter turn causing said first leg to extend in said cavity transverse to said slot and to overlap said bar, a safety pin, engageable within said slot and connected to said anchor member, and adapted to maintain said anchor member in said rotated position; a support member secured to said main leg of said anchoring member and extending laterally therefrom, said support member being of tubular shape defining a base and a top, said safety pin extending through aligned holes of said base and top, having a head over lying said top; biasing means to bias said safety pin to a locking position in which its inner end protrudes from said base to engage said slot, and means to retract said pin to disengage from said slot.

2. A handling system for a reinforced precast concrete element, such as a panel, beam and the like, comprising, in combination, such an element having an exposed surface, an elongated slot opening at said surface, said element having a cavity communicating with said slot, said cavity having a length at least equal to the length of said slot and a width greater than the width of said slot, two spaced substantially parallel rigid bars embedded in said element, each of angle shape cross-section, each defining a first wing and a second wing, the first wings of said pairs of bars being exposed within said slot and defining the lateral surfaces of the same, the second wings of the pair of bars being oppositely directed and defining the surface of said cavity closest to and parallel to said exposed surface, the transverse leg of said anchor member extending on opposite sides of said straight leg to define a T-shaped head with the T-shaped head engaging both second wings of said bars in the rotated position of said anchoring member with respect to said slot and cavity; a flanged sleeve member surrounding and rotatable about the main leg of said anchoring member, a collar surrounding and rotatable about said sleeve and retained by the flanges of the same, tightening means to tighten the transverse leg of said anchoring member against said second wings of said angle bars within said cavity said sleeve including a base plate having a central hole through which said main leg of the anchor member freely extends, said base plate being adapted to be positioned flat against said exposed surface of said element with said central hole in register with said slot, said central hole having a lateral notch and said main leg of said anchor member having a laterally-extending lug to engage said notch to prevent rotation of said anchor member with respect to said base plate and sleeve, said base plate having safety pins protruding from the underface thereof and engageable with said slot to prevent rotation of said base plate and sleeve with respect to said slot

3. A handling system as defined in claim 1, wherein a hoisting ring is carried by the outer end of said anchor member.

4. A handling system as claimed in claim it wherein said biasing means is a compression spring surrounding said safety pin between said base and top.

5. A handling system as defined in claim 2, further including a hoisting ring pivoted to said collar about an axis transverse to the long axis of said main leg, the outer end of said anchor member being threaded, said tightening means being a nut screwed on said main leg to engage said sleeve.

6. The combination of a lifting and hoisting device with a flat precast unit transportable therewith said flat unit having an inner cavity accessible from the outside by a transverse slot,said device compris-ing a tubular member defining a base and a top, said base being applied against said flat unit, said base and top having first and second aligned holes, at least one safety pin slidably engaging and projecting from said first aligned holes; an anchor member engaging and projecting from said second aligned holes and being fixedly secured to said base and top, the inner end of said anchor member extending through said flat unit and within said cavity and defining two transverse legs at right angle to the plane containing said safety pin and said anchor member, the outer free end of said anchor member being releasably mounted to a hoisting member;
said device being attached to said precast unit by raising said safety pin until the inner end thereof is flush with said base and said tubular member is oriented transverse to the slot of said cavity, so as to insert said transverse legs within said slot and into said cavity, and rotating said hoisting member and said tubular member, so as to position said transverse legs across said slot, wherein said safety pin becomes aligned with said slot and is made to protrude within said slot.

7. The system as defined in claim 6, further including a compression spring surrounding said safety pin intermediate said base and top, so that said pin be always biased by said spring to a position protruding from the underside of said base.

8. The system as defined in claim 6, said base comprising diametrically-opposite notches in said corresponding second aligned hole to receive diametrically-opposite lateral lugs carried by said anchor member, and an annular undercut surrounding the latter hole, wherein there are two safety pins secured to and protruding from the underside of said base; said cavity defining a slot; said safety pins being adapted to engage said slot upon rotation of said anchor member.