US3922135A

US3922135A - Mold for concrete C-profiles including a removeable core

Info

Publication number: US3922135A
Application number: US381037A
Authority: US
Inventors: Hans Haller; Erwin Wendl
Original assignee: WENDL DIPL ING ERWIN
Current assignee: WENDL DIPL ING ERWIN
Priority date: 1970-09-28
Filing date: 1973-07-20
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25

Abstract

A mold for concrete beams witn an upper web and a pair of depending lateral flanges, forming a C-profile, comprises an elongate outer form with two parallel walls rising from a base and a box-shaped inner form of trapezoidal cross-section resting on that base, the sides of the inner form being spaced from the walls of the outer form to define clearances for the beam flanges. The sides of the inner form carry a pair of substantially horizontal external ledges contacting the outer form in the assembled state of the mold; after the concrete has been poured, but before complete hardening, the molded beam is withdrawn together with the inner form, whose ledges support the beam flanges, from the outer form to allow use of the latter for further molding operations.

Description

United States Patent Haller et a1.

MOLD FOR CONCRETE C-PROFILES INCLUDING A REMOVEABLE CORE Inventors: Hans Haller; Erwin Wendl, both of Nibelungengasse 40, Graz, Austria Notice: The portion of the term of this patent subsequent to Oct. 23, 1990,

has been disclaimed.

Filed: July 20, 1973 Appl. No.: 381,037

Related U.S. Application Data Continuation-impart of Ser. No. 75851, Sept. 28, 1970, Pat. No. 3,767,153.

U.S. Cl. 425/432; 249/63; 249/79; 249/142; 249/158 Int. Cl. B28B l/08 Field of Search 425/432, 456; 249/50, 63, 249/79, 81, 142,144, 156,158,160,

168-l72, 175, 177; 264/D1G. 43, 33, 34,

References Cited UNITED STATES PATENTS 2,836,875 6/1958 Chandler et a1. 249/180 3,385,554 5/1968 Anderson 249/165 3,441,243 4/1969 Walz 249/81 3.539,]46 11/1970 Smith 249/63 3,767,153 10/1973 Haller et a1. 249/18 FOREIGN PATENTS OR APPLICATIONS 683,087 11/1952 United Kingdom 425/443 Primary Examiner-R0bert D. Baldwin Assistant Examiner-John MCQuade Attorney, Agent, or Firm-Karl F. Ross; Herbert Dubno [57] ABSTRACT A mold for concrete beams witn an upper web and a pair of depending lateral flanges, forming a C-profile. comprises an elongate outer form with two parallel walls rising from a base and a box-shaped inner form of trapezoidal cross-section resting on that base, the sides of the inner form being spaced from the walls of the outer form to define clearances for the beam flanges. The sides of the inner form carry a pair of substantially horizontal external ledges contacting the outer form in the assembled state of the mold, after the concrete has been poured, but before complete hardening, the molded beam is withdrawn together with the inner form, whose ledges support the beam flanges, from the outer form to allow use of the latter for further molding operations.

10 Claims, 6 Drawing Figures US. Patent Nov. 25, 1975 3,922,135

f Hi

VIBEATORS 5 MOLD FOR CONCRETE C-PROFILES INCLUDING A REMOVEABLE CORE CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of our copending application Ser. No. 75,851 filed Sept. 28, 1970, now US. Pat. No. 3,767,153.

FIELD OF THE INVENTION The present invention relates to a mold for casting C-profiles of concrete, for incorporation in a roof, platform, deck or similar structure to be made up from a plurality of precast elements of this nature.

BACKGROUND OF THE INVENTION The individual precasting of beams, planks or other elongate components of a larger concrete structure, to be assembled at a building site, has well-recognized advantages in transportation and handling over the casting of an entire structure either at the factory or on location. However, conventional technique in such cases requires the provision of a number of identical molds if several concrete bodies are to be cast simultaneously, i.e. if the pouring of the concrete for one body is to commence before the previously cast body has completely hardened.

In our copending application identified above, there has been disclosed a method of producing such profiles in staggered succession with the aid of a mold comprising an outer form and several interchangeable inner forms, the outer form defining with an associated inner form a space for the casting of a C-profile with an upper web and a pair, of depending lateral flanges which can be bodily removed from the outer form, upon a partial hardening of the concrete, together with the inner form whereby the outer form becomes available for the casting of a new profile with the aid of another inner form. The profile is allowed to set completely while remaining supported by the associated inner form, the number of available inner forms thus determining the number of profiles that can harden simultaneously.

OBJECTS OF THE INVENTION The general object of our present invention is to provide an improved composite mold to'be used for this purpose.

A more particular object is to provide a mold of this description whose inner form is robust enough to maintain the shape of the cast profile during the setting thereof, yet is of simple structure enabling such inner forms to be inexpensively produced in the number required for a given production schedule.

SUMMARY OF THE INVENTION The outer form of a mold according to our invention includes a pair of substantially parallel walls rising from a base, these walls being separated from the sides of the inner form by clearances accommodating the lateral flanges of a C-profile to be molded. The inner mold, which is removably seated on the base and is lower than the walls of the outer form, is provided with substantially horizontal external ledges extending from its sides and contacting the confronting walls of the outer form, thereby spanning the intervening-clearances. In order to enable the inner form to be lifted out of the outer form, together with a partially set c-profile having its 5 may be constituted, advantageously, by the extremities of one or more conduits for a curing fluid (e.g. steam) which traverse the inner form and project endwise therefrom. At least one pair of longitudinally spaced end members extend between the two forms acrossthe intervening clearances and rise above the inner form to the level of the walls of the outer form; these end members, or at least one of them, may be longitudinally dis-' placeable in accordance with the desired length of a profile to be molded and may be fastenable to either or both outer walls in a selected position.

According to a more specific feature of our invention, the inner form is generally box-shaped and has an upwardly converging, substantially trapezoidal crosssection giving it a slight draft to facilitate the detachment of the fully hardened profile from its sides.. We have found, surprisingly enough, that the extraction of the inner form with the partially hardened concrete body from the outer form creates no particular difficulties even if the outer walls are perfectly parallel and vertical.

A particularly sturdy inner form of a mold according to our invention has the shape of a prismatic tube with preferably solid top and bottom plates as well as end BRIEF DESCRIPTION OF THE DRAWING The above and other features of our invention will now be describedin greater detail with reference to the accompanying drawing in which:

FIG. 1 is a side-elevational view of a mold for producing elongate concrete bodies, specifically C-profiles, in accordance with our invention;

FIG. 2 is a top view of the mold shown in FIG. 1;

FIG. 3 is a cross-sectional view taken on the line III- III of FIG. 2 but drawn to a larger scale;

FIG. 4 is an elevational view of a template serving as an end member for. the mold of FIGS. 1-3;

FIG. 5 is a side-elevational view of the template shown in FIG. 4; and

FIG. 6- is a perspective view of an inner form representing one of the components of the mold.

SPECIFIC DESCRIPTION The mold shown in the drawing consists essentially of an outer form 2 and an inner form 3, the latter being removably seated on a set of transverse beams 1 constituting the base of the outer form 2. This outer form further comprises a pair of

upstanding walls

2a, 2b rigidly connected with the beams l by brackets 42 with the aid of

screws

14 and 41. The beams 1 are anchored by stirrups In to a foundation 20 (e.g. of concrete), the threaded tips of the stirrups passing through slots in the beam flanges whereby the base can be limitedly shifted laterally; centering screws 7, passing through anchors 3 7a, serve to maintain the base in the porper position on the foundation.

The inner form 3 is basically a prismatic tube with a slightly convex top 3a, sides 3b, 3c and a bottom 3d as well as end plates 10. The top, sides and bottom are assumed to consist of solid sheet material, e.g. steel, whereas the end plates are perforated to give passage to extremities 9a, 9b of a pair of longitudinally extending bars 9 which can be gripped by hooks of a crane for the purpose of lifting the form 3 off the base 1 or returning it to that base between the

walls

2a, 2b of the outer form 2. The bars 9 are shown to be tubular so as to serve as conduits for the admission of a curing fluid, such as steam or hot air, into the interior of form 3; the curing fluid may escape into the form proper through orifices (not shown) provided in one of the pipes 9 and may be exhausted by way of similar orifices in the other pipe.

The clearances between

walls

2a, 2b and sides 3b, 3c are automatically maintained by lateral bottom ledges 3e which are integral with the box-shaped body of form 3 and which contact these walls at their roots. Furthermore, as shown in FIG. 3, the sides 3b and 3c of form 3 may be provided with ancillary ledges 4 which are adjustably mounted thereon to form a false bottom above the fixed ledges 3e. Since the form 3 has a generally trapezoidal cross-section, with the sides 3b and converging upwardly, the width of the ancillary ledges 4 should be slightly larger than that of bottom ledges 3e; the ledges 4 may be elevated to a desired level, depending on the height of the flanges of a concrete profile to be cast in the mold, with screws 14 loosened to permit the

walls

2a and 2b to be moved into abutting relationship with ledges 4 so that the flanges-forming clearances dedefined by these walls and by sides 3b and 3c are practically completely closed at the bottom. in order to facilitate such adjustment, screws 14 pass through slots in brackets 42 or in the upper flanges of l-beams 1.

If the height of the concrete profile is to correspond to that of the outer mold 2, the adjustable ledges 4 may be detached so that the flanges of profile 40 come to rest directly on the fixed ledges 3e.

The length of the profile is determined by two templates 5 inserted at selected locations in the channel between

walls

2a and 2b, each of these templates comprising a horizontal bar 5a and a pair of legs 5b, 51'. Bar 50 hugs the top 3a of inner form 3 whereas legs 5b and 50 act as partitions in the clearances between the two nested forms. Naturally, templates 5 with legs of different height will be required for different vertical positions of ancillary ledges 4 if such ledges are being used.

As best shown in FIGS. 4 and 5, each template 5 is integral with a C-clamp 11 including an arm 110 which overhangs its leg 5c and defines therewith a slot 1 1b receiving the top of wall 2b of the outer form 2 upon operative insertion of the template in a selected position. Screws l2 serve to fasten the template to wall 2b in order to immobilize it with reference to the mold. The templates, therefore, have the additional function of holding the inner mold 3 in place on the base 1 the outer mold 2. Prior to extraction of mold 3 together with the partially hardened concrete profile 40, screws 12 must be loosened so that templates 5 riding the form 3 can be withdrawn together with that form and the concrete profile. Upon such extraction, form 3 with its templates and the cast body can be stored at some convenient location pending final handling of that body.

4 Prior to such hardening, as described in our copending application and patent, the concrete body may be further shaped (e.g. manually) with formations of recesses, cutouts or the like therein. Also, steam or the like may be circulated through the form 3 via pipes 9 as described above to accelerate the hardening process.

Metal reinforcements and/or prestressing cables may pass through holes 13 in templates 5 for imbedding in the concrete profile 40. The top of the casting may be made level with the edges of form 2, or slightly lower than these edges, by passing over it with a strike bar as shown and described in our copending application and patent.

in order to manufacture two or more C-proflles of reduced length on a single inner form, three or more templates 5 can be inserted into the mold at suitable locations. As seen in FIG. 5, the templates may have downwardly converging front and rear surfaces to simplify the task of extracting them from between two adjoining concrete bodies formed in this manner. A bracket 6, carried by the clamp 11, resiliently bears upon the upper edge of wall 2b to prevent canting of the template.

Vibrators 8 are mounted at longitudinally spaced locations on the two

parallel walls

20, 2b of outer form 2 and are set in operation during the pouring of the concrete into the channel between these walls, thereby insuring a uniformly dense deposit. The boundaries of this channel, i.e. the confronting surfaces of

walls

20, 2b and the outer surfaces of top 3a and sides 3b, 3c of form 3 as well as the upper faces of

ledges

3e and 4, may be provided with low-adhesion castings for easier separation from the concrete body; templates 5 can be similarly coated.

The unitary construction of inner form 3 (except for the optionally provided adjustable ledges 4 thereof) gives that form the compressive strength necessary for sustaining the stresses to which the form is subjected both within the mold and thereafter during the setting of the enveloping concrete body. It is not absolutely essential, however, that the bottom 3d of the form 3 be a continuous plate", thus, a series of transverse braces will suffice in many instances. Also, as likewise described in our copending application and patent, the form could be cast in one piece as a solid concrete beam.

1 claim:

1. A mold for casting a C-profile of concrete, comprising: an outer form including a base and a pair of substantially parallel lateral walls rising fixedly from said base; an inner form lower than said walls removably seated on said base between said walls, said inner form having sides separated from said walls by ciearances accommodating a pair of lateral flanges of a C- profile to be molded, said sides being provided with substantially horizontal external ledges spanning said clearances and contacting said walls; at least one pair of longitudinally spaced end members extending across said clearances longitudinally, subdividing same between said forms and resting on said ledges while rising above said inner form to the level of said walls; and anchor means on said inner form enabling the same to be lifted out of said outer form together with said end members and with a molded C-profile having lateral flanges supported by said ledges.

2. A mold as defined in claim 1 wherein said base comprises a multiplicity of spaced-apart cross-beams rigid with said walls.

3. A mold as defined in claim 1 wherein said inner form has an upwardly converging, substantially trapezoidal cross-section.

4. A mold as defined in claim 1 wherein said inner form has a top and a bottom complementing said sides to a horizontal tube of polygonal cross-section.

5. A mold as defined in claim 4 wherein said tube has substantially closed ends provided with said anchor means.

6. A mold as defined in claim 4 wherein said ledges are at the level of the bottom of said tube.

7. A mold as defined in claim 1 wherein at least one of said end members is longitudinally shiftable along 6 said inner form and is provided with fastening means for releasably securing it in a selected position to at least one of said walls.

8. A mold as defined in claim 1, further comprising vibrator means mounted on each of said walls.

' 9. A mold as defined in claim 1, further comprising conduit means passing through said inner form for conducting a curing fluid therethrough.

10. A mold as defined in claim 9 wherein said conduit means is provided with at least one pair of extremities projecting end-wise from said inner form, said extremities forming part of said anchor means.

Claims

1. A mold for casting a C-profile of concrete, comprising: an outer form including a base and a pair of substantially parallel lateral walls rising fixedly from said base; an inner form lower than said walls removably seated on said base between said walls, said inner form having sides separated from said walls by clearances accommodating a pair of lateral flanges of a C-profile to be molded, said sides being provided with substantially horizontal external ledges spanning said clearances and contacting said walls; at least one pair of longitudinally spaced end members extending across said clearances longitudinally, subdividing same between said forms and resting on said ledges while rising above said inner form to the level of said walls; and anchor means on said inner form enabling the same to be lifted out of said outer form together with said end members and with a molded C-profile having lateral flanges supported by said ledges.

7. A mold as defined in claim 1 wherein at least one of said end members is longitudinally shiftable along said inner form and is provided with fastening means for releasably securIng it in a selected position to at least one of said walls.

9. A mold as defined in claim 1, further comprising conduit means passing through said inner form for conducting a curing fluid therethrough.