CA1084246A - Machine and forms for precasting concrete products - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Machine and forms for precasting concrete products wherein dry mix is deposited in casting cavities defined by mating upper and base form sections, vibrated and/or pressure compacted, and the upper form section removed immediately for curing of a free standing green cast product. A single upper form section cooperates with a number of base sections and the latter are used to transport the green cast products for curing. Auto-matically separable base section parts may also be employed for the transport of cured products. Forms are adapted for fork lift handling and include high intensity vibrators, sight openings for ascertaining a cavity full condition, closure plates for fill openings, pressure applying and finishing de-vices, and sectionalized construction for various size products.
Casting machine includes mix delivery apparatus and form hand-ling apparatus for upper and base form sections for automated casting and transfer of green cast products for curing.

Description

1~89~Z~6 ~CHINE A~D FORMS FOR PRECASTING CONCRETE PRODUCTS ~:

BACKGROUND OF THE INVENTION

Dry mix or no slump concrete having a relatively low moisture content has been used in ~he manufacture o~ concrete pipe in rotary packerhead machines and the like for some time and satisfactory pipe has been produced at comparatively high rates of production. Other types of precast concrete prod~
ucts, however, have been conventionally produced employing a wet mix casting process. In a wet mix process, the moisture .
content of the mix is substantially higher than in a dry mix 1~ process, and the conventional practice includes the deposi-tion of mix in forms and the subsequent during of the cast products with the forms in place. Curing may continue for a period of twelve to sixteen hours to reach approximately one : fourth the full strength of *he concrete and the forms are then stripped from the cast product and the product subse-quently aged for a period of fourteen to twenty eight days to reach full strength. While the wet mix casting process has proven generally satisfactory for low volume production, severe drawbacks are encountered in adapting the process to a high volume production operatian. The process is inherent~
ly slow and a large number of expensive forms are required. -~

It is the general object of the present invention to provide a machine and forms for the precasting of concrete products ; in a dry mix process which are particularly well adapted to . 25 high volume and low cost production. ~:

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further object oE the invention resicles in th~ provision of a castin~ machine and Eorms as mentioned wherein dry mix is deposited in a casting cavity and vibrated and/or sub~ect d to external pressure whereby to eliminate voids and to com-pact the mix and to thereby form a yreen cast product havingsufficient initial structural inteyxity for self support, the product being thus adapted to immediate curiny in a free standing condition with its form removed.

A still further object of the invention resides in the pro-provision of a casting machine and forms as set forth where-in separable Eorms of a specific design permit the use of a single upper form section with a plurality of base form sçc-tions and thus effect substantial savings in the cost of forms~

A still further object of the invention resides in the pro-vision of a casting machine and forms as set forth wherein immediate removal of an upper form section upon completion of casting effects substantial reduction in curlng time and thereby enhances high volume and low cost manufacture of con-crete products.

A still further object of the invention resides in the pro-vision of a casting machine and forms as set forth wherein sectional form construction with upper and base sections per~
mits the use of the base sections for the post casting trans-fer of green cast products and the post curing transfer oEcured products.
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Still another object of the invention resides in the provi-sion of a casting machine and forms as set forth wherein the forms are provided with sight openings for visually ascer-taining the completion of form filling operations, with clo-sure means for filling and thereafter compacting mix in a casting cavity, and with pressure applying and finishing means for compacting dry mix in the cavity. ~`

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~ _3_ \( Still another object of the invention resides in the provision of a casting machine and forms as set forth wherein the forms are constructed in separable sections so as to provide various ~.
size cast products with major portions of the forms usable throughout a range of product siz~s.

SUMr~L~RY OF THE INVENTION

The present invention provides in a machine for the dry mix precasting of concrete products and having at least one casting station; the combination compr.ising a plurality of like base ~orm sections each adapted for detachable assembly with an~
beneath a mating upper form section, a means for supporting said base form sections exposed ~pwardly at said casting station so that said sections may be successive~.y assembled with a mating upper form section, a downwardly open upper form section at said casting station having similar spaced apart generally ver-tically extending parallel wall defining portions and at least one interconnecting cross member defining portion communicating at opposite ends with the wall portions, each o~ said wall de-fining portions having an upwardly exposed fill opening at the top, power operating and vertical guide means for effecting relative vertical movement between said upper form section and a mating base form section at said casting station, said means serving to ef~ect relative vertical movement to assemble said form sections so that the base section closes the bottom of the upper section and the two form sections cooperatively form a a casting cavity, and said means serving to effect further relative vertical movement to disassemble said form sections after casting so that the upper form section is stripped from the green cast product with the product supported and standing free atop the base form section, dry mix delivery means at said casting station operative~y associated with said upper form section for the deposition of mix in said casting cavity through said fill opening, vibrating means at said station operatively associated with said assembled form sections for compacting and eliminating voids in the cast product, means having operative .
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-3a-and inoperative positions relative to said fill openings in said wall portions of said upper form section, said means in the operative position serving in cooperation with said vibra-tiny means to engage overfilled dry mix at said fill openings and, finish the engaged surface and compact the mix throughout the casting cavity.

In fulfillment of the foregoing objects, the present invention involves the provision of a form having at leas-t two mating sections comprising an upper sectlon and a base se~tion. The upper section is open downwardly and is provided with a fill opening and the base section closes the upper section at the bottom to cooperatively form a casting cavity. Preferably, a plurality of base sectio~ are provided and each base section is adapted for assembly with the upper form section. A dry mix or no slump concrete is deposited in the casting cavity with the upper and base form sections assembled and the form is vibrated during and/or after mix deposition to eliminate voids and to compact the mix therewithin so as to form a green cast product haviny sufficient initial structural integrity for self support.
The upper form section is then removed prior to the occurrence of any substantial curing time and may in fact be removed im-mediately to expose the green cast product and to allow the same to stand free on the base section of the form. The base section of the form is thereafter employed to transfer the green product for curing and, when a two part base form section is employed, one part of the form may be employed for further product transfer subsequent to curing.

The compaction and elimination of voids in the dry mix may also ;
be achieved by the application of external pressure at a region of mix overfill and su~h operation may occur with or without simultaneous form vibration. Pressure bars may also serve a concurrent pressure application and surface inishing function.

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. , ' ' ', ` . . "" . . ' . ' ~. '' . . ' ' , ' '' ' . ' ' , ' ' . ' ' When a plurality of ~ase Eorm sections are employed, the ul-tima-te in savinys in -the cost of Eorms and enhanced produc-tion ra-tes are achieved. A single upper form section may be employed for successive assembly with the base form sections and after casting and immedia-te removal of the upper form section, the base sections may be employed successively to transfer green cast products for curing and subsequent s-tor-age.

The invention is particularly well suited to the production of precast monolithic concrete units having spaced apart gen-erally parallel walls and at l~ast one interconnecting or .cross member. When such units are produced and the foxms so configured with fill openings at the tops of wall portions, sight openings may be provided at a top wall of a cross mem-ber portion of the form in order to determine the progressionof the dry mix into and upwardly to the top of the cross mem-ber portion. When the mix appears at and is forced outwardly through a centrally located sight opening, completion of.the fill operation is insured. Further, the invention may involve the provision of forms with cross member portions having a fill opening at the top and an associated closure means, wall portions of the forms also having fill openings at the top.
Mix is then deposited in all three fill openings, the cross member fill opening is thereafter closed.by the closure means, and vibration and/or.the application of pressure effects the necessary compaction and void elimination. Compac~ion through pressure applica~ion may also be achieved with forms having cross member portions permanently closed at the top.

Pressure applying and finishing means of the invention are preferably adapted.for movement between operative and inoper-ative positions respectively for the application of pressure and a finishing operation and for clearance of the fill open-ings during deposition of the dry mix into the casting càvity. ..
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Two part base form sections preferably include an automati-35 cally separable fea~ure. When the two parts of the base .
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sections are assembled they support green cas-t products sub-stantially throughou-t the area of their lower s~lrfaces for transfer from a Casting Sta-tion to a Curing Station. This provides substantial suppor-t for products which may tend t~
be somewhat fragile and which must be care~ully handled prior to curing. When one part of a base section is engaged sepa-rately by a lift means, it automatically separates from the other part of the section whereby to lift a cured product by engaging only a portion of its lower surface. At this point in time, the product has attained full strength and the risk of damage to or rupture of the product is substantially lessened.

Horizontally separable sectionalized forms also provide for the use of parts of the forms in common for the production of products over a range of sizes. In particular, the forms configured for the monolithic unit mentioned above may be provided with two or more selectively usable center parts of the cross member portion of the upper ~orm section. Thus, monolithic units having cross members of various length can be produced at a substantial savings in the form cost.
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BR~EF DESCRIPTION OF THE DRAWINGS - -Fig. 1 is a perspective view of a concrete product which may be formed with the machine and forms of the present invention, the product taking the form of a monolithic concrete unit comprising spaced apart parallel walls and an integral inter-connecting cross member or arm.
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Fig. 2 is a perspective view of a sectional form configured for the unit of Fig. 1, the form comprising upper and base sections in an assembled condition, and a dry mix delivery means in association with the form and including a mud pan atop the form.
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Fig. 3 is a perspec~ive view of an upper section of the form of Fig. 2.
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Fic~. 4 is a per~pective view oE a base section of the form of Fig. 2.

Fig. 5 is a perspective vi~w of the mud pan of Fi~. 2.

Fig. 6 is a fragmentary sectional view of a portion of the upper form section taken generally as indicated at 6-6 in Fiy. 3 and showing a portion o~ a mud pan in operative asso-ciation therewith.

Fig. 7 is a fragmentary sectional view of a poxtion oE the form section of Fig. 3 taken generally as indicated at 7-7 in FigO 3 and showing a portion of a mud pan in operative asso-ciation therewith.

Fig. 8 is a perspective view illustrating a form base section and a green cast unit supported thereon.

Fig. 9 is an exploded perspective view showing two parts of a 15 form base section and a cured ca~t unit in an elevated posi- -tion and supported by one part of the base section.

Fig. lO is a perspective view showing an upper section o a form comprising a second embodiment oE the apparatus of the invention.
, Fig. 11 is a perspective view showing a base form section adapted to mate with the upper section of Fig. 10.

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Fig. 12 is a perspective view oE a monolithic cast unit de-rived from the orm oE Figs. 10 and 11.

Fig. 13 is a somewhat schematic elevational view of a casting machine for handling the form sections of the preceding fig-ures, an upper form section being shown in an elevated posi-tion.
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Fig. 14 is a~urther somewhat schematic elevational vie~ Ot the casting machine of Fig. 13 with the upper form section in .: :.:: ,: :

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a low~red position and in assembly with a base form section for castiny a concrete produc-t therewithin.

Fig . 15 is an end elevational view of the form of Figs. 10 and 11 with the sections thereof in assembled condition and with dry mix deposited therein during a casting operation.

Fig. 16 is a fraymentary vertical section through the form of Fig. 15 and showing a manually operable presser and finishing bar.
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Fig. 17 is a further somewha~ schematic elevation of the cast-ing machine showing an upper form section elevated and show-ing a green cast product on a base form section at a second station in the machine, a lift means for the base form sec tion and the product also being illustrated.
., Fig. 18 is an exploded end elevation of the base section of 15 the form o Figs. 10 and 11 and a cured cast product on one ;~
part of the base section.

Fig. 19 is a perspective view of an upper section of a hori-zontally separable sectionalized form and illustrates one mating part of the form.

Fig. 20 is a perspective view similar to Fig. 19 but showing a second mating part of the form.

Fig. 21 is a perspective view showing an intermediate part of the upper form section oE Figs. 19 and 20.

Fig. 22 is an end elevational view showing the parts of the form of Figs. 19 and 20 in assembled condition.
, Fi~. 23 is an end elevakional view showing the form parts of Figs. 19 and 20 in assembled condition.
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Fig. 24 is an end elévational view showing the form parts of .. , . ~ , ..... . . . . ~ . ~ ~ . . .. : . .. .

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Figs. 39 alld 20 .i~ c~s.sembly with ~n in-termedia-te form part somewhat longer -than -the for~ part of Fig. 22.

Fig. 25 is a perspective view showing a monolithic cast con-crete unit of -the type produced with the form of Figs~ 19 et sequa.

Fig. 26 iS a side elevation view of a form provided with a pressure applying and finishing apparatus movable between operative and inoperative positions.

Fig~ 27 is a.somewhat enlarged fragmentary vertical section taken generally as indicated at 27-27 in Fig. 26, and illu-strating the operation of the pressure applying and finish-ing apparatus.

DESCRIPTION OF PREFERRED EMBODIMENTS

The machine and forms of the present invention may be employed in the production of a wide variety of precast concrete pro-ducts. One such product is illustrated in Fig. 1 and showld be regarded as illustrative only. The product shown is a monolithic precast unit indicated generally at 10 and which has spaced apart generally vertical walls 12, 14 in parallel .:
20 relationship and with an integrally formed interconnecting or ..
cro~s member 16. A single cross member or arm 16 is illustra-tea but it will be understood that the unit may require a pair o such arms at opposite ends or at intermediate locations.
The particular configuration oE the unit is derived from the re~uirements of retaining wall construction and may vary widely. The unit shown i.s known in the trade as a STA-WAL
unit and is further illustrated and described in U. S. Patent No. 3,877,236, entitled CRIB BLOCK AND STRUCTURE, filed on October 5, 1973 in the names o:E Raymond J. O'Neill and George David Newell, and issued on April lS, 1975 In accordance with the invention, precast products such as the unit 10 can.be produced in quantit~ and at low cost employing '''' . ' " , ,' ', ~.

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~ 6 c~ dry mi~ proc~ss. The dry mix process ~ItiIizes a "d~y mix"
or "no slump mix" of the type used in the manu~acture of con-cret~ pipe in rotary pack~rh~d machines and the like. A dry mix includc~ cemen-t, acJcJregate and water in relative propor-S tions substantially diffe:rent from a conven-tional wet mix.
The moisture content in a convention~l wet mix may fall in the range fLve to ten per cent (5~ ~o 10%~ whereas the moisture content in a dry mix may fall in the substan-tially lower range one to four (1% to 4%). A wet mix flows readily in reaching remote areas in a form but must be cured for a substantial period oE time with the form in place as explained above. A
dry mix, on the other hand, does not flow ~s readily but when properly compacted, the form may be removed prior to the pas- ~.
sage of any substantial curing time and in fact in~ediate form removal is possible. That is, if the dry mix i5 sufi-ciently compacted and voids eliminated, the cast product will have sufficient initial structural integrity for self support and will be capable o standing free with its surface exposed . or curing immediately on completion of the casting operation.
The machine and orms of the present invention take full ad-vantage o the characteristics of a.dry mix casting process in effecting substantial reduction in the cost of forms and in providing automated high production rate casting and cur-.
ing operations.
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The invention includes orms illustrated in a first embodi-ment in Figs. 2 through 9, the forms being constructea in conigurations corresponding to the unit 10 of Fig. 1. It will be apparent, however, that.novel features of construc-tion of the orms can be readily adapted to the casting of a wide variety o concrete products. An upper orm section indicated generally at 18 is best illustrated in Fig. 3 and .a lower or base form section indicated generally by the refer-ence numeral 20 is best illustrated in Fig. 4. In accordance with khe presently preerred practice, a single upper form 35 section 18 is provided or cooperation with a plurality of .
base ~rm sections 20, 20, each of the base sections 20 being :
adapted to mate with the upper form section 18 and to define .. .

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a castiny cavity in coopera-tion therewi-th. The upper form section 18 opens downwardly and is p~ovidecl with at least one fill openin~ for -the deposit.ion of dry mix in the casting cavity. ~s illustrated in Fiy. 3, the upper form section 18 has spaced parallel and generally vertically ex-tending wall portions 22, 24 and a cross member defining por-tion 26. Each of said portions is provided with a fill opening at the top and, as shown, wall portion 22 has a fill opening 28 which ex- .
tends substantially th.roughout its length and a similar fill 10 opening 30 is provided at the top of the wall por~ion 24. A
fill opening 32 at the top of the cross member por~ion 26 also extends substantially throughout the length thereof.

The upper form section 18 is of heavy steel construction and may include a plurality of vertical bracing members such as 15 34, 34 welded on plate steel which defines the wall portions 22, 24. Cross bracing members such as channels 36, 38 may also be provided for rigidity. Precise tolerances in the finished product may thus be assured together with the integ-rity of the form section during intense vibration of the form ..
and the dry mix deposited therein. A single vibrator 40 is illustrated on the form wall portion 24 and may be permanent- .
ly mounted or merely engaged with a vibrator supporting plate .
42. Pref.erably, intense vibration is effec~ed at the upper form section 18 and at each of the three portions th`ereof.
That is, a vibrator such as 40 is preferably mounted on the opposite wall portion 22 and.a third vibrator is mounted on .
the connecting or cross member portion 26 of the form, neither shown.

While vibration has been employed in wet mix processes, low .
intensity snake type vibrators have been conventionally em-ployed. The mix flows readily and vibration merely eliminates "pock marks" and other small defects on the surface of the cast product. Vibration in the present process assists in :~
mix flow when employed during deposition of the mix and com- :
pacts the mix when employed during and/or subsequent to depo-sition of the mix. Preferably, vibration is employed both .
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duriny and subsequent to mix deposition and with products such as the unit 10 yood compactio~ and void elimination has been attained wi-th vibration continued for a period of one or two minutes after the casting cavity has been filled with mix~
High intensity vibration is preferred and good results have been achieved with 8,000 to 12,000 pounds of force at frequen-cies in the range of 6,000 to 10,000 vibrations per minute.

In Fig. 5, a "mud pan" indicated generally at 44 is employed in association with the upper form section 18. That i5, the mud pan 44 is disposed atop the fo~m sec-tion 18 to facilitate the deposition of the dry mix into the casting cavity through the fill openings 28, 30 and 32. Corresponding openings 46, 48 and 50 are provided in the mud pan 44 and the opening 50 has depending wall~ 52, 54 which define the opening 50 adja-cent the opening 32, Fig. 7. In Fig. 6, it will be seen that the mud pan opening 46 aligns with the opening 28 in the form wall portion 22 for the downward entry of mix to the casting cavity defined by the form. Preferahly and as illustrated, the mud pan 44 is fixed atop the upper form portion 18 as by welding at 56, 58, Figs. 6 and 7. With the mud pan so arran-ged dry mix may be delivered as from a chute 60, Fig. 2 which may be movable relative to the mud pan and when the mix is de-posited on the flat surface 62 of the mud pan an operator may use a trowel or the like to urge the same toward and into the openings 46, 48 and 50. With vibrators such as the vibrator 40 operating during and/or after the deposition of the dry mix .
to the casting cavity, the operator may use the trowel to finish the exposed upper surfaces of the walls 12 and 14 and the cross member 16 o~ the unit 10. Compaction of the mi~
and void elimination in this embodiment of the invention is accomplished by intense vibration as mentioned and by manual pressure exerted by an operator in his manipulation of a tro-wel at the fill openings 28, 30 and 32.
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The base section 20 of the form shown in Fig. 4 serves to close the bottom of the upper form section 18 when the two form sections are assembled as in Fig~ 2. Detachable connec-., ', ' ' , ,.

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:L~38~ 46 tin(J means may be provicled Eor the two orm sections but, asillustrated, the force of yravity is reliecl upon and the upper form section 18 m~rely rests on -the base form section 20. For proper aliynment of the Eorm sections two (2) sm~ll inclined S alignment bars 62, 62 are preferably provided. When the upper form section 18 is shaped to provided the monolithic cast unit 10 of Fig. 1, the base section 20 is correspondingly shapea and has spaced apart base plates 64, 66 ~or the lower surfaces of wall portions of the unit 10 and a base plate 68 for the lower surfaces of cross member portion thereof. The plate 68 is somewhat elevated above plate 64, 66 and inclined plates 70, 72 at each end thereof e~-tend to the plates 64, 66 respectively.
The base configuration of the unit 10 also has maryinally ex-tending stepped-up portions formed by base plates 72, 74 and -lateral bracing may be provided as at 76, 76.
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As will be apparent, the lower surface of the unit 10 is sup-ported throuyhout its area by the base section 20 of the form as illustrated in Fig. 4. Thusj during casting the upper form section 18 is completely closed at the bottom by a base section 20, and subsequent to casting when the green cast unit 10 is capable of supporting itself, the form sections 18, 20 may be separated with the unit 10 left exposed and standing free on the base section 20. A green cast unit 10 is so illustrated in Fig. 8 atop a base form section 20. In this condition, the unit 10 is ready for curing and may be transferred to a curing kiln or the like. In practicing the invenkion, a conventional kiln has been employed and a steam cure for a period of 12 to 16 hours has been ound to result in cast un}ts 10, 10 reaching their full skrength. This o~ course compares most favourably with a cure of 12 to 16 hours for wet mix casting prior to form stripping and an aging period of 14 to 28 days for the attain-ment of full strength.

As mentioned, a plurality of base form sections 20, 20 may be prov~ded and by successively mating the base sec-tions with the upper section 18, units 10, 10 may be successively cast and transported for curiny in a free standing condition atop the ~ .

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base sections. The casting operation can be accomplished in an extremely short periocl oE time thus accommodatin~ high volume production of the units 10, 10. For example, casting has been accomplish~d at a daily production rate of 40 to 50 units per S 8 hour shift. This is to be compared with wet mix production rates of approximately 8 to 10 units per day with the same la-bour cost and with 8 to 10 expensive forms in use. Obviously, - it is much less expensive to employ a plurality af base form sections 20 and a single upper form sectlon 18 than to provide a plurality of complete or unitary forms as in a wet mix pro~
cess. Further, a substantial improvement is achieved in qual-ity control. With individual forms for each unit in a wet mix process, variation in form tolerances results in dimensional variations in the cast units. With a single upper form section in the dry mix process identical cast units are produced and retaining walls contructed therefrom have superior character-istics.

As mentioned, the base form sections 20, 20 are preferably provided in two parts wi-th one part adapted to support a unit 10 over only a portion of its lower surface and with the two parts in assembly adapted to support the unit substantially throughout the area of its lower surface. In the assembled condition of Fig. 4 the base form sec-tion 20 supports the unit 10 throughout the area oE its lower surface, Fig. 8. One part of the base section 20 is, however, separable from the remain-ing or other part thereof and comprises the plate 68. The plate 68 is supported by two smal} flanges 78l 78, Figs~ 4 and 9, and is movable vertically relative to the remaining or other par* of the base section 20. That is, t~he plate 68 is held in position in Fig. 4 by gravity but may be lifted Erom the flanges 78, 78 as illustrated in Fig. g. When so lifted, the plate 68 supports the unit 10 only throughout a central portion of the lower surface of the cross member 16 but is nevertheless usable for further transfer of the unit~ The unit 10 in Fig. 9 is illustrated subsequent ~ curing and, having reached its full strength, can be readily supported and transported by the plate 68. Thus, when the unit 10 requires fu11 support prior to , - ~ - - . .

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curin~ ~s in F~ig. 8, the base section 20 is cap~ble of supply-ing such support. Subsequen-t to curing and when there is no da~cJer of structural damage to the unit as might .result from partial support, the plate 68 serves eEficiently for fur-ther transport of the uni~. Fast and efficient ~orm stripping is thus provided for and base Eorm sections are available imme~i-ately for reuse.

The manner in which the base form sections 20 are constructed to provide for the transfer of units 10, 10 thereupon may vary within the scope of the invention. Preferably, ~he base sec-tions are lifted from below and at least one access opening is provided for lifting the assembled base section and a second access opening for lifting its said one part, the plate 68.
As shown, a pair of access openings 80, 80 are provided for lifting the assembled base section 20 and such openings are adapted for the insertion of spaced horizon~al fork members 84, 84 of a fork lift device. Similarly, a pair of access openings 82, 82 are provided for lifting the plate 68 and said openings are adapted for the receipt of the fork members 84, ~4 of a fork lift device. Obviously, a fork lift truck may be employed as well as an overhea~ fork lift device. Handling of :
the green or uncured units 10, 10 should be precise and accom- . ;
plished with due care when the assembled base sections 20 are lifted with the units thereon. The units are somewhat fragile 25 in their uncured-state as mentioned and must be handled accor- .
dingly. When the units 10, 10 are transferred or otherwise handled subsequent to curing by lifting the same on the plates 68, 68 the need for extreme care is no longer in evidence.
Obviously, the units 10, 10 may be stacked or otherwise stored and the plates 68,.68 returned to their base form sections 20, ..
20 for reuse o~ the sections. An excess number of plates 68, -68 may be provided for interchangeable use with the remaining or other parts of the base sections 20l 20.

Figs. 10 and 11 illustrate respectively upper and base form ~ :
sections 18a and 20a adapted to produce monolithic cast units 10a as shown in Fig. 12. The unit 10a is substàntially iden-, .- ... ... ; . .

Z~6 tical with the un:i~. 10 oE ~ig. I but has round~d or beveled edc3es sllch as the beveled edc3es 86, 8~ for the elimination of sharp corners and areas o~ stress. The form sections 18a, 20a are accordingly substarltially iden~ical with the form sections 18, 20 described above but ~he construction of the sections 18a, 20a has been subs-tantially simplified. End plates 88, 88 ex tend between wall portions 22a, 24a in upper Eorm section 18a and a channel 90 extends between the end plates and is secured to the cross member portion 26a. Fill openings 28a and 30a are provided at the top of the wall portiOns 22a, 24a but thP top of the cross member portion 26a i5 closed by a top wall 92.
The top wall 92 has at least one small opening therein in ac-cordance with the invention and, as best illustrated in Fig.
15, a series of five (5) equally spaced openings 94, 94 are provided in the plate. A central opening 94 extends through the plate 92 and the channel 90 so as to be visible from above.
The openings 94, 94 are for a purpose to be set forth below.

The base section 20a has a vertically movable plate 6~a and fork lift access openings 80a, 80a for lifting the a~ssembled base section as in Pig. 8. Fork lift openings 82a, 82a beneath the plate 68a permit lifting of the plate 68a with a curea unit 10a thereon as in Fig. 9.

The form sections 18a and 20a are obviously less expensive to manufacture than the form sections 18, 20 illustrated and des-cribed above. Further, the casting operation is slightly differ-ent with thefoxm sections 18a, 20a. Rather than filling the cross member 26a through a fill opening at the top, the dry mix is deposited only in the fill openings 28a, 30a and pro-~resses gradually from each of the wall portions 22a, 24a into and toward the center of the cross member 26a, Fig. 15. That is, the dry mix first progresses from each end of the cross mem-ber 26a toward the center and then gxadually rises in the cross member portion 26a as indicated by broken lines 96, 98, 100 in Fig. 15. The gradual progression of the mix into and upwardly in the cross member portion 26a is caused by intense vibration and/or the application of pressure to the dry mix at the fill ' , - ' ' : ~' ' -' ~

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OpellillC3S 28a, 30a. Thus~ vibra-tors such as 40a, Fig. 1~ are provided on the form upper section 18a, preferably at three loca-tions as mentionecl above, and the vibrators may be operated during the deposition of mix and/or subsequent thereto. Pres-sure may be applied to the mix at the Eill openings 28a, 30a bymanual or power operated means and, as illustrated in Fig. 16, an elongated pressure applying and finishing bar 102 may be provided for manual manipulation.

The openings 94, 94 serve as visual indicators to the operator that the mix is progressing as desired into the cross member 26a of the form section 18a. At a minimum, a single opening 94 may be provided and located approximately centrally in the wall 92 and when mix appears at the opening and is forced up-wardly therethrough, the operator is assured that the cross mem- -ber is completely filled. Altexnatively, and as best illustra ted in Fig. 15, a series of openings 94! 94 provides visual indication of the progress o~ the mix upwardly and toward the center of the cross member portion 26a. The mix will appear initially at the outermost openings 94, 94, then at the next inwardly spaced openings, and finally at the centrally located opening 94. When the mix has appeared at all of the openings and is forced upwardly therethrough, the operator can be assured that the cross member portion 26a is completely filled.

Figs. 13, 14 and 17 illustrate a casting machine for automating the present invention. The form sections 18a, 20a are shown in use in the machine but it will be apparent that the form sec-tions 18, 20 are equally adaptable for such use as well as other types o~ forms for precast products o~ various configurations and sizes. The casting machine, indicated generally by the reference number 104, includes a support means for form base - sections 20a or the like and which is adapted to mount the base sections in an upwardly exposed attitude at a Casting Sta~ion A. Preferably, and as illustrated, the support means takes the form of a rotary turntable 106 which may be power driven from below by conventional means and which is movable or index-ible through at least two and possibly additional positions.
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~L~8~6 That i.s, -the turntab1e 106 may be indexecl to position a form 20a as illustrated at the Casting Station A in Fig. 13, and may then be fur~her indexed to move -the base section 20a to the broken line pos.ition of Fic~. 13 at a second or TransEer Station B. In operation, base sections 20a, 20a may be ~ounted in suc-cession at the Station ~ Eor subsequent casting of products or, alternatively, a third statlon on the -turntable 1~6 may be used for mounting the base sections and they may thereafter be in-dexed to the Station A. When a product has been cast atop the ; 10 base section 20a at the Station A, the table may thereafter be indexed to the Station B for transfer o~ the base section 20a and a green cast product thereon.

The casting machine comprises a massive frame structure at the Station A which provides for support and rigidity of the vari-ous machine elements and which may comprise two or more verti-cal frame members 108, 110 connecte~ at the top by horizontal frame member 112. An upper form section such as the section 18a is arranged at the Casting Station A and relative ver-tical movement is provided for between the form sections 18a and 20a for assembly and disassembly respectively for casting and for stripping of the upper form section from a green cast product.
As shown, the base form section 20a is maintained stationary in the vertical direc~ion and the upper form section 18a is movable between upper and lower positionsrelative thereto.
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In Fig. 13, the upper form section 18a is shown elevated and supported by vertically movable horizontal frame 114. ~he frame 114 has depending form support mem~ers 116,.116, two shown but four preferred, and which rigidly support the form section 18 against accidental or unintended horizontal displacement.
The frame 114 may be guided from the vertical frame members 108, 110 by conventional means such as roller or slide devices so as to move:precisely in a desired vertical path and to ef-fect a.similar movement of the form section 18a. Thus, when the form section 18a is elevated subsequent to a casting opera~ ~ ;
tion the section is precisely stripped vertically from a green cast unit lOa and surface marring or other damage to the unit ' ' ' ' ' ~

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is avoi~ed.

In moving the frame 114 upwarclly and downwardly -to effect move-ment of the ~orm section 18a between its upper and lower posi-tions, power operating means are preferably provided in the form of fluid cylinders 120, 120. The fluid cylinders 120, 120 may be mounted on the horizontal cross frame member 112 as shown with their actuating rods 122, 122 operatively connected with the frame member 114. Appropriate valving and other control devices may of course be provided for the requlation of cylin-der operation and frame and form section movemen-t.

In operation of the casting machine 104, the upper form section 18a is moved downwardly from the position shown in Fig. 13 into assembly with the base se~tion 20a as illustrated in Fig. 14.
A dry mix ~elivery means which may take the form of a conveyor 124 thereupon delivers mix 126 to a further delivery means 128 atop the form section 18a. The delivery means 128 may take the form of a pair of mix guide and distribu-tion plates arranged in an inverted V so as to direct mix to the fill openings 28a, 30a, Fig. 15. When the casting cavity has been filled, vibra-tion and/or the application of pressure at the Casting Station A, the dry mix within the form is ~ompacted for initial sel~
support and the upper form section 18a may be raised to its up-per po~ition as illustrated in Fig. 17 in a stripping operation.
The turntable 106 may then be indexed to move the base section 20a to the Transfer Station B with the green cast unit 10a thereon, and a next succeeding form base section 20a may be in-dexed to the Station ~ as illustrated.

At the Transfer Station B an overhead fork lift device indica-ted generally at 130 comprises a pair of fork members 132, one shown in broken line, and an L-shaped frame member 134 suppor-ted from a lift device 136. The ~ftdev~136 is movable both ver-tically and horizontally so as to permit the fork me~bers 132, 132 to enter the access openings 80a, 80a, Fig. 18, and to lift the base section 20a thereby lifting the cast unit there-on. On transfer to a curing kiln and subsequent to curing, the - plate 68a may be lifted by a fork lift truck to effect further L~L 6 tr~nsfer of the ~inish~d unit lOa, Fi.g. ].8.

Another cmbodiment of the :Eorms oE the present invention is illustr~ted in Figs. .L9 through 2~. Sectional:ized uppe.r form sec-tions adap-ted for horizon-tal separation and for the use of interchangeable intermedia-te parts provide for monolithic cast units lOb of the type shown i.n Eig. 2~ with varying dimensions of their cross members or arms 16b. rh~ unit lOb i.s generally similar to the units shown and desc.ribed above, but it will be noted that the top of the cross member or arm 16b includes op-positely downwardly inclined surfaces 131, 133 meeting at a central line of juncture. The unit lOb is ths smallest of a series of units having arms 16b of varying.length. When units lOb with longer arms are desired, they are formed with flat central sections as suggested by the assembled form parts of Figs. 22 through 24.

Mating left and right hand parts 134, L36 of an upper form sec- .
tion are illustrated respective~y in Figs 19 and 20. Flanges 138, 140 may be bolted or otherwise secured together to provide an assembled upper form section for use in casting the unit lOb of FigO 25. The part 134 has a fill opening 142 and the part 136 has a fill openlng 144, the openings being located respectively at the top of wall portions 146 and 148. A left hand part 150 of the cross member portion has a fill opening 152 and a right hand part 154 has a ~ill opening 156. Asso-ciated with the fill openings 152 and 154 are closure members having operative and inoperative positions respectively for . closing of the openings and for opening the same for the depo-sition of dry mix therethrough. The closure means ta~e the form of slidable plates 158, 160 and they are preferably auto- .`
matically operable respectively by small fluid cylinders 162, 164.

As will be apparent, the form parts 134, 136 may be assembled atop a suitably shaped base form sectionj not shown, and dry mix deposited through the fil~ openings 142, 144, 152 and 1~6.
The plates 158, 160 may thereafter be moved to their closed . - . ;

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positions ~Ir~ mix compacti~ ccomplish~d by vibration and/or the application of pressure at the ~ill openin~s 142, 144.
The Eorm parts ~re pref~rably provided wi-th vibrators not shown at each w~ll portion and at the cross mernber portion th~reo~. Pressure applyin~ meaIIs may be manual or power oper-ated as will be described hereinbelow.

An intermediate part 166 of the upper form sectiorl of Figs. 19 and 20 is illustrated in Fig. 21. Flanges 168 and 170 are adapted respectively for assembly with the flanges 138 and 140 on the form parts 134, 136. The form part 166 has a fill open-ing 180 and an associated plate 182 operable by fluid cylinder , 184 for opening and closing oE the opening~ When the form parts 134, 136 and 166 are assembled as illustrated in Fig. 23 and are pos~tioned atop a suitable base section casting may proceed as described above. A further intermediate form part 186 illustrated in Fig. 24 may be similarly employed with the form parts 134, 136 for the casting oE a unit lOb having a somewhat longer cross member or connecting arm. All operation's carried out with the forms described above may be similarly carried out with the sectionalized forms bf Figs. 19 through ~4. ;~

Figs. 26 and 27 illustrate an upper form section 18b which is provided with a power operated pressure applying and finishing device. The form section'l8b may be substantially identical with the form sections described above but it should be noted that its cross member portion preferably includes a fill open-ing with a closure means or, alternatively, a permanently closed top wall. Com~ac~ion of the dr,y mi~ through the appli- ' cation of pre,ssure is besk achieved with a casting cavity'which 30' is closed throughout except for the area of pressure application.
Further, it is the preferred practice to combine pressure compac-tion with vibration compaction and it may'be assumed that the ' form 18b is provided with one or more vibrators as described above~

The form section 18b has a fill opening along the top'and sub-stantially throughout the length of each of its wall portions and on~ such openinc3 is illu~t:rat~cl a-t 188 in Fig. 27. Thus, a sincJle power operat~d pressure apply:ing and finishing device is iLlustratecl genc~cllly at l90 bu-t it will be understood that a pair of such d~vices is required when two ~2) fill openings such as 188 are provided.

The device 190 includes a pressure'applying and finishing mem-ber or bar 192 which is movable vertically in one and an oppo-site direction and operable to apply pressure to dry mix in an overfill condition at the fill opening 188 in ~ig. ~7. That is, the bar 192 is mo~able vertically downwardly toward and into a slot 194 defined in a mud pan 196 mounted a-top the upper form section 18b. Preferably, a two to three inch overfill condition is provided at the fill opening 188 and the bar 192 is urgPd downwardly into engagement therewith to compress the ' 15 overfill and to provide the desired finished surface at 198 at the top of the fill opening. The under surface o the bar 192 may be shaped to finish the surface 198 in any desired configur-ation and is flat in the form shown in Fig. 27.' Substantial ' compaction of the confined dry mix occurs throughout the mass of the cast unit and a high level of compaction occurs in a localized zone beneath the finished surface 198. The surface 198 also receives a uniform and accurate fi'nish throughout.
~rhis is particularly des'irable in the case of the monolithic ' units of the type illustrated at 10, lOa, and lOb since the sur- ' face 198 is a bearing surface. Substantial pressure is applied to the mix and excellent results have been achieved with the application of pressure in the range of 50 to 150 pounds per sguare inch. Good localized compaction beneath the surface 1~8, good compaction and void elimination throughout the mass of the unit are achieved with the application of pressure in this range and with simultaneous vibration of the form. It should be noted, however, that the method o~ the invention is ' not so limited and that the application of compaction'pressure may be accomplished with or without simultaneous vibration.

Actuation of the presser and finishing bar 192 is accomplished by a horizonta~ frame member 200 which supports the bar 192 on : ,. ., :::

-thre~ (3~ dep~nding rod~ 2~, 202, FiCJ. 26. l~he fr~me rnember 20~ is swing~ble through an a~c as i:llustx~ated in Fig. 27 be-tween operative and inop~rative po~.itions with -the bar 1~2 elevated from -the slo-t L9~ as i Llus trated in broken line form in Fiqs. 26, 27. In its operative position, the ~rame 200 can be movecl vertically downwardly to in -turn effec-t downward move-ment of the bar 192 and the application o pressure to the overfill in the slot 1~4. :~n its inoperative posi-tion, the frame 200 swings the bar 192 downwardly and rightwardly in Fig.
27 ~'or clearance during the cavity filling operation.

Preferably and as shown, vertical movement of the frame 200 and bar 192 is effected by means oE a pair oE fluid cylinders 204, 206 mounted respectively at opposite ends of the form sec-tions 18b. The'cylinders 204, 20~ have actuating rods 208, 210 respectively connected with opposite end portions of the frame memher 200. Suitable control means for the cylinders effect the required'upward and downward movement of the frame 200 and the bar 192.

The cylinders'2~4,' ~06 are mounted on pivot plates 212, 214 which have associated pivot pins 21b, 218 in turn mounted on plates 220, 222 secured to the form section 18b. As will be apparent, the plates 212, 214 may be manually swung about their respective pivot''pins to effect swinging movement of the frame member 200 between i~s opera~ive and inoperative positions. In its upper or opera*ive position, the frame member 200 must be accurately located for precise downward entry of the bar 192 in the slot 194. Accordingly, locking or locating pins 224, 22~, one shown, may be provided for entry through suitably aligned '' openings in the plates 214, 222 and 212, 220.
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As will be apparent frorn the foregoing, a casting machine and associated ~orms particularly well suited to high volume pro-duction have been provided. An important feature of the inven-tion resides in the vibration and/or pressure compaction of dry mix in a casting cavity and the resulting green cast product which has su~ficient initial structural integrity for self support. This permits -the immecliate s-tripping of an upper form section and tAe subsequent immedia-te curiny of the green cas-t prod~lct standin~ free on a base form section. ~rhe provision of a plurality of base form sections ~or cooperation with a single upper form section not only accommodates high produc-tion techniques but results in substantial savings in the cost of forms. The automation of the process in a power operated casting machine effec-ts further savings in time and the ability to cure the products immediately in an exposed and free stand-ingi condition effects a drastic reduction in the time neededto attain fuli streng-th of the finished product. In the aggre-gate, the improvements achieved convert the former slow and tedious we-t mix process to a true high volume production opera-tion.

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Claims (19)

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

1. In a machine for the dry mix precasting of concrete products and having at least one casting station; the combination com-prising a plurality of like base form sections each adapted for detachable assembly with and beneath a mating upper form sec-tion, a means for supporting said base form sections exposed upwardly at said casting station so that said sections may be successively assembled with a mating upper form section, a down-wardly open upper form section at said casting station having similar spaced apart generally vertically extending parallel wall defining portions and at least one interconnecting cross member defining portion communicating at opposite ends with the wall portions, each of said wall defining portions having an up-wardly exposed fill opening at the top, power operating and vertical guide means for effecting relative vertical movement between said upper form section and a mating base form section at said casting station, said means serving to effect relative vertical movement to assemble said form sections so that the base section closes the bottom of the upper section and the two form sections cooperatively form a casting cavity, and said means serving to effect further relative vertical movement to disas-semble said form sections after casting so that the upper form section is stripped from the green cast product with the pro-duct supported and standing free atop the base form section, dry mix delivery means at said casting station operatively associated with said upper form section for the deposition of mix in said casting cavity through said fill opening, vibrating means at said station operatively associated with said assem-bled form sections for compacting and eliminating voids in the cast product, means having operative and inoperative positions relative to said fill openings in said wall portions of said upper form section, said means in the operative position ser-ving in cooperation with said vibrating means to engage over-filled dry mix at said fill openings and, finish the engaged surface and compact the mix throughout the casting cavity.

2. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 1, wherein said means for supporting said base form sections is operable to move a base section thereon between first and second positions respec-tively at said casting station and a second station in the machine, and wherein transfer means is provided for removing a base form section from said second machine station with a free standing green cast product thereon.

3. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 2, wherein each of said base form sections is provided with a fork lift access opening, and wherein said transfer means includes at least one fork lift element insertable in said access opening for lifting and trans-fer of the base section and a cast product thereon.

4. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 3, wherein said trans-fer means takes the form of an overhead fork lift apparatus movable both vertically and horizontally and operable to raise a base form section and its cast product from said support means at said second machine station and to thereafter transport the same horizontally.

5. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 1, wherein said support means for said base form sections maintains a base section ver-tically stationary at said casting station, and wherein said power operating and vertical guide means is operatively associ-ated with said upper form section to effect vertical movement thereof between lower and upper positions respectively for assembly with and disassembly from a base form section at the casting station.

6. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 5, wherein said support means for said base form sections includes a rotary turntable operable selectively to support and to position a base section at said casting station and at a second station in the machine removed from said casting station.

7. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 5, wherein said power operating and vertical guide means includes a vertically movable frame supporting said upper form section for movement there-with, and at least one fluid operable cylinder for vertically moving said frame.

8. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 7, wherein said machine includes a massive rigid frame structure for supporting said fluid cylinder, said movable frame, and said upper form section, and wherein said movable frame is guided for precise vertical movement along said frame structure.

9. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 5, wherein said vibra-ting means takes the form of at least one vibrator mounted on said upper form section and operable to provide vibration in range of 8,000 to 12,000 pounds of force and 6,000 to 10,000 vibrations per minute.

10. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 1, wherein said cross member defining portion of said upper form section has a top wall with at least one small opening approximately at its cen-ter for visual determination of filling of said form portion.

11. The combination in a machine for the manufacture of precast concrete products as set forth in Claim 10, wherein each form is provided with a series of small openings along the top wall of its cross member portion, and wherein said openings are visually inspected during mix deposition to ascertain the pro-gress of the mix flow centrally and upwardly in the cross member portion.

12. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 1, wherein an up-wardly exposed fill opening is provided at the top of said cross member portion of said upper form section, and wherein a movable closure means is provided for said fill opening.

13. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 12, wherein said closure means is of the sliding type and is provided with an operating means in the form of a fluid operable cylinder moun-ted on said upper form section.

14. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 1, wherein said pressure applying and finishing means includes a pair of elon-gated finishing bars associated respectively with said wall portion fill openings and each having associated power opera-ting means causing said bars to exert pressure in the range 50 to 150 pounds per square inch.

15. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 14, wherein each of said finishing bars has an associated supporting frame swingably mounted on said upper form section for movement between operative and inoperative positions, and wherein said power operating means take the form of fluid cylinders opera-tively associated with said supporting frames for urging the finishing bars downwardly in said fill openings for pressure application.

16. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 1, wherein said interconnecting cross member portion of said upper form section is constructed in at least two vertically divided detachable parts, wherein at least one intermediate cross member part is provided for assembly between said two detachable parts where-by selectively to provide cast products having interconnecting cross members of at least two different lengths.

17. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 16, wherein a plurality of intermediate cross member parts of different lengths are provided, cast products having cross members of several different lengths being thus provided.

18. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 17, wherein each of said cross member parts is provided with a fill opening at the top, and wherein each of said parts has a movable closure member associated with its fill opening.

19. The combination in a machine for the manufacture of pre-cast concrete products as set forth in Claim 18, wherein at least two vibrators are provided and mounted respectively on said wall portions of said upper form section.