US2624928A - Press for molding concrete building elements - Google Patents

Description

Jan. 13, 1953 L. D. LONG PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS l4 Sheets-Sheet 1 Filed June 21, 1948 4 a ll I Leonard any ' L. D. LONG PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 Jan. 13, 1953 14 Sheets-Sheeg 2 u Leona'rdDLong (LA Mg (New L. D. LONG PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June' 21, 1948 Jan. 13, 1953 14 Sheets-Sheet 5 LeonardBLong Jan. 13, 1953 1.. D. LONG 2,624,928

PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS l4 Sheets-Sheet 4 Filed June 21, 1948 am f ii'iig] Jan. 13, 1953 D. LONG 2,624,928

PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 14 Sheets-Sheet 5 LeonardBLong Jan. 13, 1953 v LONG I 2,624,928

PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 14 Sheets-Sheet 6 LeonardDJlong M WMLM Jan.v 13, 1953 Filed June 21, 1948 L. D. LONG 2,624,928

PRESS FOR MOLDIIJS CONCRETE BUILDING ELEMENTS l4 SheetsSheet 7 Qwuamlom LeonanlBLong Jan. 13,1953 D. LONG 2,624,928

PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 14 Sheets-Sheet 8 Leonard aLong L. D. LONG PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 Jan. m, 1953 i4 Sheets-Sheet 9 Leon ardD.Long

YLMJLM D. LONG PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 Jan. 13, 1953 14 Sheets- Sheet 10 Jan. 13, 1953 D. LONG PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 l4 Sheets-Sheet ll Jan. 13, 11953 1.. D. LONG 2,624,928

PRESS FOR MOLDING CONCRETE BUILDI NG ELEMENTS Filed Juhe 21, 1948 14 sheets-sheet 12 Jan, 13, 1953 D. LONG' 2,624,928

PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 19 8 14 Sheets-Sheet 1a Jan, 13, 1953 1.. D. LONG PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Filed June 21, 1948 14 Sheets-Shet 1 Patented Jan. 13, 1953 UNITED STATES TENT OFFICE PRESS FOR MOLDING CONCRETE BUILDING ELEMENTS Claims.

The present invention relates to apparatus for producing pre-cast building elements.

Apparatus now in use for producing pre-cast building elements are ordinarily only adapted for the manufacture of very small elements, for example, concrete or cinder blocks of very small dimensions. Furthermore, the blocks thus produced are almost invariably of the same design or shape.

An object of the present invention is to provide apparatus for making prefabricated building elements and which apparatus is readily capable of producing elements having a size range varying from the order of one foot up to at least twenty feet in length and which elements may be widely varied as to shape or design.

Another object of the invention is to provide an apparatus for producing pre-cast building elements in quantities and wherein the molding procedure will require a minimum of time and mechanical operations.

The apparatus of the present invention are such that elements of different sizes and shapes can be produced by use of matrices, core elements, spacers, and dividers provided by the invention. These various forming elements provided by the invention are so designed that they can be changed and shifted by unskilled labor. Because the filling of the forms and most of the other steps involved in the operation of the apparatus and the carrying out of the method do not require skilled labor, the cost of operating the apparatus is extremely low.

Another object of the invention is to provide an apparatus whereby the elements can be formed within an extremely short space of time, usually a matter of minutes, so that only a small number of mold units need be provided in a single plant.

Other objects and advantages of the invention will be apparent from the following specification and accompanying drawings.

Figure 1 is an end view of the apparatus, with the extreme upper portion being omitted, and one mold unit being shown in vertical section on the line H! of Figure 4.

Figure 2 is a side view of the Figure 1 structure, the view looking toward Figure 1 from the left. Portions of vertically extending members of the apparatus are broken out in Figure 2 and Figure 4 is a top plan view of some of the mold units illustrated in Figure 1, with portions broken away as in Figure 2.

Figure 5 is a fragmentary side elevation looking toward the righthand portion of the mold unit of Figure 4 from the bottom of Figure 4.

Figure 6 is a fragmentary transverse vertical section on the angled line 66 of Figure 2 and showing an adjustable width mold unit.

Figure '7 is a transverse vertical section through a mold unit on the line 1'! of Figure 3.

Figure 8 is a transverse vertical section through a mold unit on the line 8-8 of Figure 4.

Figures 9, 10 and 11 are transverse vertical sections taken on the line 9-9 of Figure 3 and illustrate successive steps in the operation of a mold unit.

Figure 12 is a view similar to Figures 9 to 11 and shows a later step in the operation.

Figure 13 is taken on the line |3l3 of Figure 12 and shows the mold unit of Figures 9 to 12 in side elevation.

Figure 14 is a transverse vertical section on the line I l-l4 of Figure 4.

Figure 15 is a fragmentary longitudinal vertical section on the line l5--l5 of Figure 14.

Figure 16 is a transverse vertical section on the line I6I6 of Figure 4.

Figure 17 is a transverse vertical section on the line l'I-l'l of Figure 15.

Figure 18 is a transverse vertical section on the line l8l8 of Figure 15.

Figure 19 is a View of a core element used in the mold unit of Figures 14 to 18.

Figure 20 is an exploded view showing matrices used in a mold unit, the matrices being shown in bottom and top view, respectively, and including a dotted line showing of cores assembled with the lower matrix.

Figures 21 and 22 are side view of cores.

Figure 23 is a side view of a spacer.

Figure 24 is a side view of a second form of spacer, with portions broken away.

Figure 25 is a view of a chimney flue supporting element which may be formed by the apparatus.

Figure 26 is a view of a core used in forming the element of Figure 25.

Figure 27 is a view of upper and lower matrices used to form the element of Figure 25.

Figure 28 is a transverse section on the line 2828 of Figure 4.

Figure 29 is a top view of a mold unit fitted with a matrix and cores in readiness for pouring.

Figure 30 is a transverse vertical section of a mold unit equipped for casting the flue supporting element of Figure 25, the section being taken on the line 3030 of Figure 31.

Figure 31 is a longitudinal vertical section on the line 3 l3l of Figure 30.

Figure 32 is a central vertical section of a mold unit for casting cylindrical elements.

Figure 33 is a transverse horizontal section on the line 33-33 of Figure 32.

Figure 34 is a transverse section on the line 34-34 of Figure 32.

Figure 35 is an exploded view showing the two matrices used in the Figure 32 unit.

Figure 36 is a view of a cylindrical tubular element formed with the unit of Figures 32 to 34.

Figures 37 to 42 are views of structural elements which may be formed by th apparatus of the invention.

Figure 43 is a vertical transverse section on the line 4343 of Figure 45 of a modified form of mold unit.

Figure 44 is a detail horizontal section on the line 44-44 of Figure. 43.

Figure 45 is a view partly in vertical longitudinal section on the line 45-45 of Figure 43, and partly in side elevation (looking toward Figure 43 from the right).

Figure 46 is a transverse vertical detail section on the line 46-46 of Figure 45, and

Figure 47 is a horizontal detail section on the line 414'! of Figure 45.

General description of apparatus and operation The illustrative embodiment of the invention disclosed herein may be generally described as including mold units such as are respectively designated by the letter A, B, C and D in Figures 1 and 4, that designated F in Figure 32 and the unit indicated as FA in Figures 43 to 47. Each of the six units is adapted for molding or shaping various types and sizes of structural elements. Figures 1 and 4. show the four mold units A to D mounted in the same supporting frame G. However, it frequently will be more convenient to mount each unit in a single frame such as G or to mount a number of units of a single type in the same frame. As shown in Figure 1, the mold units of that figure are positioned on a platform 8 fixed substantially intermediate the height of frame G, the platform being, formed by crosspieces 9 (Figure 3).

The mold units A and B are of different widths and are particularly adapted? for formation of structural elements El and E2 such as illustrated in Figures 37 to- 41 which are provided with spaced cavities or recesses therein. The unit C is generally similarto the units A and B but is so constructed as to be adjustable for forming structural elements of various widths.

The mold unit D is particularly intended for production of hollow slabs, columns Or building course elements E3 of rectangular section suchas illustrated in Figure 42-.

The mold unit F shown in Figure 32 is particularly adapted for forming tubular structural elements E4 of cylindrical section such as illustrated in Figure 42.

The mold unit FA shown in Figures 43 to 47 is used to form the same structural elements that can be formed by the units A, B and C of Figures 1 to 4 but operates in a diiferent manner from that of the units A, B and C.

The elements El, E2 and E3 shown in, Figures 37 to 4'2 and mentioned above; are. disclosed and claimed in my application; for Ere-Cast Building 4 Elements and Buildings, Serial No. 744,464, filed April 28, 1947.

The mold unit A illustrated in Figures 1, 4 and 7 may be generally described as including upri ht and spaced longitudinal wall elements I and I2 adapted to define or mold two longitudinal surfaces li x and l2zn of a structural element of the type illustrated at El in Figures 37 and 38. As is best shown in Figure 3, the ends of the unit A are fitted with inter-engaging wedge elements l4 bearing against a fixed end plate IE3 and the innermost wedge element of each set will usually define an end I ia of the structural element El. Referring to Figure 7, a plate l8 is provided at the bottom of unit A, plate l8 being fixed to frame G and of less width than the space between the wall elements l3 and I2. In the space on each side of plate l8 the unit A will be provided with vertically extending ejectors 20 which, as illustrated in Figure 3 are spaced lengthwise of the unit. It will be noted from Figures 1 and 3 that the lower ends of the ejectors 20 are fixed to a table H vertically movable in the lower portion of frame G.

When concrete is to be poured in unit A to form a structural element such as El of Figures 37 and 38, th upper ends of the ejectors 23 (Figure 7) will be below the upper surface of the bottom plate l8 and a matrix 22 of the form shown in Figure 20 will be placed in unit A to rest on plate 53 and the ejectors. The matrix 22 is provided with ribs 24 and 26 on its upper surface which will form corresponding recesses 24.7: and 26.1: (Figure 38) in the element El to be cast. It also will be observed that matrix 22 is of open-frame farm so as to include spaced longitudinally extending bars 23 and 29 joined by spaced crossweb-s 3t and 3!. As is indicated by dash lines in Figure 20, cores 32 and 34 such as shown in Figures 21 and 22 will be fitted between the webs of the matrix. The cores will be secured to the bottom plate it of the unit by bolts, as shown in Figure 12. Then the wedges l4 will be driven tightly between each end plate [6 of mold unit A and the adjacent matrix 22 as shown in Figure 3. This assembly is shown in top plan in Fig- Concrete, preferably a fairly dry mixture such as hereinafter described, will now be poured into the space above the matrix and between the cores and the inner surfaces of the vertical plates of the mold unit. Assuming that the structural unit is to be metal reinforced, after the concrete has reached a height of about two inches above the matrix 22, suitable metal reinforcing rods may be laid upon the concrete. The alternate placing of reinforcing elements and pouring of concrete can be continued until the mold has been filled to a level approximating that illustrated in Figure 9. Then the matrix 36 of Figure 20 will be placed upon the top of the mass, as also illustrated in Figure 9, the matrix being centered in the mold unit by engagement with the mold unit vertical walls.

It will be observed that matrix 36 is of the same form as matrix 22 in that it includes longitudinally extending bars 23' and 29' and cross webs 33 and El. However, the matrix 36 is provided with recesses 33 and 40 so that it will form ribs 330: and 461: (Figure 37) on the upper edge of the element El. As shown in Figure 3, the cross webs and SI of the matrix 33 will lie between the upper ends of the cores 32 and 34. These webs 39' and 3 l and the cooperating webs 30 and 3| on the lower matrix 22 will respectively form the upper and lower surfaces of cross webs 30a: and

am as well as the upper and lower surfaces of the end walls Mm of the structural element El being produced.

All of the surfaces of the mold unit, including the fixed walls of the mold, the matrices, cores and end wedges, which come in contact with the concrete will be coated with metal and will have oil applied thereto before concrete is poured into the mold unit. This, will not only enable the concrete element to have a smooth surface, but will insure that after the molding operation has been completed, the formed element readily can be stripped from the mold unit.

The next step of the operation will be to position the press element J above the mold unit A. As best shown in Figures 1, 3 and 9, press element J is supported by a beam or carriage K provided with rollers 45 at each end to engage trackways 48 at each end of the top of frame G.

Cylinders 56 are fixed to carriage K and are connected to a suitable source of fluid pressure. The press element J is fixed to pistons 52 movable in the cylinders 58. Carriage K is movable transversely of the supporting frame G and when the press element has been vertically aligned with the mold unit A, as shown in Figure 9, by draulic pressure may be applied to the cylinders 58 to force the press element downwardly. The degree of pressure used may be 400 lbs. per square inch and upwardly to as high as 600 lbs. per square inch. Even the latter figure is not a limit if the formed element must have a greater strength than would be obtained with that pressure.

It will be observed that the amount of con crete or other material to be placed in the mold must be so gauged that, with the desired pressure applied to move the upper matrix 36 down into the mold, as shown in Figure 10, the element El will have the proper height. Then press element J will be raised from matrix 35 as shown in Figure 11.

With the press element now moved from above the mold, a transporting carrier or conveyor L of the type shown in Figures 12 and 13 will be positioned above the mold. The carrier Lis an open box-like frame suspended from wheeled trucks 53 movable on a track 54 fixed in frame G above mold unit A. Carrier L is adapted to be raised or lowered by means of sheaves 56 so that a pair of spaced and longitudinally extending beams 58 included in carrier L will be respectively positioned above each upper longitudinal edge of the mold unit A. Then the wedges it at the ends of the mold unit are loosened. The table l-I carrying the ejectors 29 then will be raised as shown in Figures 12 and 13 so that the upper ends of the ejectors will lift the lower matrix 22 and the structural element El supported thereby, so that matrix 22 will be above and clear of the cores 32 and 3d and the upper edge of the mold unit A. As the result, element El and the matrices 22 and 36 will be stripped from the mold unit outer walls and by a movement along the line along which molding pressure was applied.

As is shown in Figure 12, element El and the matrices will now be within carrier L and the lower surface of matrix 22 will be just above the beams 53 of carrier L. Suitable crosspieces 52 will then be positioned upon the beams 58 and beneath matrix 22. The ejectors 2t will then be lowered, or the carrier L lifted slightly, so that the matrix 22 will rest upon the crosspieces. Carrier L will then be moved along its track 5% to convey the formed element El and the matrices out of the apparatus to a. curing point.

The formed element and matrices can immediately be removed from the carrier and the matrices stripped from element El. Element El can then be subjected to suitable curing as hereinafter described, when it will be ready to use for building purposes.

After all of the mold units, or any desired group thereof, have been filled, the press element J can be successively positioned above them to compress their charges. Then all of the formed elements can be simultaneously lifted by raising ejector carrying table H. Finally, a carrier L can be moved about each raised concrete element so that it can be removed for curing. The whole operation obviously requires but a few minutes.

As is hereinafter described in detail, the mold units will preferably have heating elements 64 associated therewith, usually in the form of steam pipes. These may be positioned alongside the exterior of each unit, as shown in Figure 1, so that the units will be heated sufficiently to drive off moisture in the mass of concrete. However, the molding operation is not ordinarily prolonged in any way to provide for heating. In other words, the principal purpose of the heating elements is to keep the units fairly hot and thereby assist in drying the concrete, but the molding operation preferably does not include any separate heating period.

Referring again to Figures 1 and 4, the mold unit B is of the same type as the mold unit A, just discussed, except that it is somewhat narrower. The mold unit C shown at the left of Figure 1 is similar to the units A and B, but is so constructed as to be of adjustable width. As is hereinafter explained in detail, the invention includes various devices which can be fitted on the molds to enable elements of less length than the molds to be simultaneously produced in one mold, as well as to vary the form of the finished element.

The mold unit D, shown at the right of Figure l, and adapted to form hollow elements of rectangular outline such as shown in Figure 42, includes a core 66 best shown in Figure 19, which is longitudinally movable through the mold.

Further with regard to mold unit D, after press element J has been lifted from it, the core 66 can be withdrawn lengthwise of the unit so that the formed structural element E3 can be Detailed structure of apparatus of Figures 1 to 31 Referring to Figures 1 to 3, the frame G is mounted on a suitable foundation l5 and includes spaced uprights 16 at the front end of the apparatus, 1. e., the end viewed in Figure 1 and the end shown at the right in Figures 2, 4 and 13 and at the left in Figure 3. Similar uprights ll are spaced at the rear of the apparatus, the four uprights thereby forming the corners of the frame G.

As best shown in Figures 1 and 2, the uprights on each side of the apparatus are joined near 7 their lower ends by longitudinally extending beams '18 which support the spaced cross beams 9 of the fixed platform 8 on which the mold units A to D are supported. Referring to Figure 1, vertically extending tracks 19 are provided inwardly Of the uprights I6 and TI and beams 18 and these trackways guide rollers 88 journalled on the vertically movable table H which carries the ej'ectors' 20. The trackways T9 extend from the base of the apparatus to the fixed platform 8. Table H is secured to plungers or rams 8i movable in thefoundation 15 by means of fluid pressure or other suitable means. The transversely extending trackways 49 for the carriage K which supports press element J are secured to the uprights T6 and ll.

As is best shown in Figure 3, carriage K primarily comprises a lower horizontal beam 85, an upper beam 85 and two vertical beams or uprights 86. The beams 84 and 85 extend the length of the apparatus and are secured together by the uprights 86. The underside of lower beam 84 carries the rollers 46 to engage the trackways 48. Each upright 86 has a roller 8'! iournalled thereon to engage the side of the As is illustrated in Figures 1 and 2, a rotatable shaft 99 is journalled below the upper beam 85 between the uprights BG-a-nd-a plurality of sheaves or pulleys 9| are fixed to shaft 98. Cables 92 secured to the sheaves extend downwardly to a bar 99, secured to the press element J by vertically extending rods 94 which may pass through apertures or guides in beam 84 of carriage K. The press element J is welded 01' otherwise secured to the rods 94. In other words, bar 93, rods 94 and press element J comprise an element vertically movable upon carriage K. The sheaves or pulleys 9| will all be actuated together by the drive sheave 95 shown at the left of Figure 2 and which is adapted to be actuated by means of a chain 96.

It will be observed that with the pressure in the cylinders 50 released, bar 93 and press element J can be raised and lowered together by operation of the chain 96. For example, when the press element J is to be operated, it can be lowered to a point adjacent the mold unit by operation of chain 96 and then lowered the remaining distance by fluid pressure acting in the cylinders 50.

Figures 1 to 3 do not show the extreme upper portion of the frame G which is illustrated in Figures 9 to 13 (Figures 9 to 13 are broken away to exclude the carriage K and press element J discussed in the immediately preceding paragraphs). As is illustrated in Figures 9 to 13 the" fixed uprights T6 and 11 at the corner of frame G extend a substantial distance above the press-carrying carriage K and, at their upper ends, each pair of uprights is joined by a cross beam 91. The cross beams 91 support the trackways 54', one of which is fixed above each of the mold units A to D. As has been stated above in the general description, the trackways 54 support the trucks 53 for the sheaves 56 and cables 98' carried by these sheaves support the transporting carriers L, one of which is provided for each mold unit. The trackways 54 extend outwardly and beyond the front end of the apparatus so that the formed concrete elements can be moved to a point entirely clear of the remaining operating elements before they are taken from the carriers L.

Referring now to the mold unit A and, more particularly, to Figure 3, as has been stated above, this unit includes a bottom wall I8 secured to the spaced cross members 9 of the fixed platform 8. The two end cross members 9 of the platform 8 carry the end wall brackets I5, As illustrated in Figure 7, the side walls I9 and I2 of the mold element, which preferably are U-beams, are also supported on the cross members 9. As best shown in Figure 3, the bottom plate I8 of the mold unit A extends the length of the unit. A bar 99 extends beneath the beams 9 and. parallel to mold bottom plate I3. Between the cross members 9 and directly beneath the bottom wall I8 of the mold, bar 99 carries spacers I09 as shown in Figures 3 and 28. By this arrangement, the bottom plate I 9 of the mold is securely supported throughout its entire length. As is best shown in Figure 28, the upper surface of the bottom plate I6 of the mold is provided with a central and longitudinally extending rib or shoulder IBI. This shoulder is adapted to cooperate with a groove I92 (Figures 21 and 22), formed in the undersides of core elements such as- 32 and 34 to center the core elements, in addition to the core centering action provided by the matrices 22 and 36. The manner in which shoulder IBI cooperates with matrix 22 is hereinafter described. The core elements are removably bolted to the bottom plate IS by means of bolts IOla (Figure 12) which pass through apertures IOIb (Figures 21 and 22) in the cores and aligned apertures in bottom wall or plate I'8. The cores will be of a width corresponding to the space between two opposed ejector fingers 20 or, stated another way, will have the same width as the bottom plate I8. If the core elements are formed of wood, they may be covered with sheet metal to provide a smooth surface.

Assuming that the mold unit A is to be used to form a concrete element E! of the type illustrated in Figures 37 and 38, a matrix 22 such as illustrated at the bottom of Figure 20 will be positioned within the mold unit. As is best shown in section in Figures '7 and 8 and in plan in Figure 29, each longitudinally extending bar 28 and 29' of the matrix will lie between an adjacent side wall I9 or I2 of the mold unit and the opposed side wall of the bottom plate I8, while the cross webs 39' and (H of the matrix 22 will extend across the top of the bottom plate I8. It will be observed from Figure 7 that the lower edges of the cross webs 3| and 39 of the matrix are cut away so as to be above or recessed with respect to the lower edges of the longitudinally extending bars 23 and 29 of the matrix. Hence, the cross webs can lie upon the matrix while the longitudinally extending bars lie alongside it. In addition, a notch I92 in each cross web of the matrix will fit the rib I M which extends along the bottom plate IS. In other words, the matrix 22 rests upon and straddles the bottom plate I8 and the longitudinal bars 28 and 29 of the matrix rest upon the ejector fingers 29 and the crossbeams 9 of the frame, while the cross webs of the matrix rest upon the bottom plate I8; The outer surface of the 9 longitudinal panels or bars 28 and 29 of the matrix will be in close contact with the side walls l and I2 of mold unit A.

It will be observed from Figure that matrix 22 is provided with two cross webs 3| adjacent each end, the cross Webs of each pair being spaced by a distance corresponding to the distance between the longitudinal bars 28 and 29 so that a square pocket I05 is formed. This pocket is of a size to closely receive the core element 34 of square cross-section. The upper surfaces of the end pairs of cross webs 3! lie fiush with the upper surfaces of the bars 23 and 253, although the rib 26 extends above this surface.

The other cross webs 3!] of the matrix 22 are arranged in pairs, the two webs of each pair being spaced by a distance corresponding to the distance between the longitudinal bars 28 and 29 of the matrix 22 to form other rectangular pockets H36 of a size to fit the rectangular core 3 illustrated in Figure 22. The spaces It! between adjacent pairs of webs will be relatively long to fit the longer cores 32 illustrated in Figure 21.

The side bars 28 and 29 of matrix 22 have ribs 24 extending upwardly therefrom, which ribs terminate at the innermost surface of each end cross web 3|. The ribs 24 and will form grooves 24a: and 26x, respectively, in the opposed surface of the element El of Figure 37.

In order that the inner cross webs 302s of the element El of Figures 37 and 38 will be of less height than their side panels Illa: and l2x, the webs so of matrix 22 will project upwardly and beyond the side bars 24 as indicated in Figure 20.

When lower matrix has been positioned in the mold unit A to form its bottom wall, the two parts of each wedge element l4 may now be forced into tight engagement with each other and the adjacent ends of matrix 22 and the brackets IS. The innermost surface of each inner Wedge element will thereby define the end surface of the structural element El which is to be cast or molded. It is desirable that when the wedges are in final position, they should not project above the side walls l0 and I2 of the mold unit.

A core element 34 will now be fitted in the pockets IE5 at each end of the matrix 22, as well as the pockets H36, and a core element 32 will be fitted in each of the other and longer pockets it! of the matrix, all as shown in Figures 3 and 29. The concrete for the element El will now be poured. As has been indicated above, assuming that the element El is to be metal reinforced, after about 2 inches of concrete has been poured, a reinforcing element of proper form maybe laid upon the concrete. The pouring of additional I concrete can be alternated with the placing of reinforcements, with a final pouring of concrete. Thus, the mold unit A is now completely filled as shown in Figure 9.

After the mold has been filled with concrete as described above, the matrix 36 will be laid upon the concrete as shown in Figure 9. As is indicated in that figure, all factors are so related that when the proper quantity of concrete has been placed in a mold unit to form a structural element of the desired height, the upper edges of the side and end walls of themold will extend somewhat above the level of the batch of concrete so as to serve as a centering and guiding means for matrix 35. Also, as shown in Figure 3, the

10 upper ends of the cores 32 and 36 will also extend upwardly above the batch of concrete to engage the pockets I05, I06 and I0! of the upper matrix 3'6 to further center the same. As is indicated in Figure 20, the upper matrix 35 is identical with the lower matrix 22 except that its lower surface is provided with recesses 38 and 453 instead of the ribs 24 and 28 formed on the lower matrix. If desired, the upper matrix may have its nonforming surface (shown uppermost in Figure 9) provided with notches I83 so that it may be used as a lower matrix and will thereby closely fit and straddle base plate It.

With the matrix 36 now positioned on the mold unit A, the carriage K will be moved transversely of the trackways 48 to carry the press element J to a point above mold unit A and matrix. Then press element J will be lowered to the position shown in Figure 9 by operation of the cable or chain 95. Pressure will then be delivered to the cylinders 59 so that the press element J will be forced downwardly to the position indicated in Figure 10, forcing the matrix 35 downwardly with respect to the core elements and the side and end walls of the mold unit. The upper edges of the mold unit walls it and I2 will usually function as a stop for the downward movement of press element J.

Immediately the batch of concrete is placed in the mold unit, the fact that the unit is heated by means of the steam pipes 64 will start a drying action with regard to the moisture in the batch of concrete and this drying action will continue during the time that the concrete is in the mold unit. In addition, as is hereinafter mentioned, the concrete used with the present apparatus and method is an extremely dry batch.

The application of pressure to the batch requires only about two or three minutes and as soon as the press action is completed, the press element J is moved upwardly to a position such as indicated in Figure 11 and then moved along trackways G8 to be clear of the mold unit. Then the carrier L illustrated in Figures 12 and 13 is moved inwardly along the upper trackways 54 to a point directly above the mold unit. After the wedge elements It have been loosened, the table H carrying the ejectors 20 is then raised by means of fluid pressure acting upon the pistons or rams Bl. As a result, the ejector fingers 20 will move upwardly from the position indicated in Figures 9 to 11, thereby acting upon the under surface of the lower matrix 22 to strip the formed element El from the side walls and cores of the mold unit A. It will be observed that this stripping action involves a translational movement of the formed element El with respect to the side walls of the mold unit and along the line alon which pressure was applied. Because the matrices 22 and 36 move with the element El and also because all surfaces of the unit are smooth and oiled as mentioned above, there will be no tendency for the edges of the concrete element to be broken away during this stripping of the element from the side walls and cores of the mold unit. Aside from this, it is found that if an extremely dry mixture of concrete is used of the proportions hereinafter described, the ap plication of at least 400 lbs. pressure per square inch will so compress the batch of concrete that there is no tendency for any portion of the element to break away during the stripping action.

The raising of the formed element El and the matrices 22 and 36 will continue until the lower surface of the matrix 36 is sufiiciently far above the lower bars 58 of carrier L to permit an operator to. place the cross bars 62 upon the bars 52. Then the ejector-carrying table H maybe lowered so that the ejector fingers 20 will move down Wardly and the matrix 22 will come to rest upon the cross bars 62. Carrier L can then be lifted to clear the trackways 48 shown in Figure 13 and move from the apparatus along its trackway 54. The element El is then lifted from the carrier L while still supported upon the matrix 22.

Referring now to the mold unit B illustrated in Figures 1 and 4, this unit is of identical construction with the unit A described above except that it is of less width. Therefore, unit B may be used to make exactly the same form of precast elements as can be made with unit A, except that the elements made with unit B will ordinarily be of less width than those made with unit A.

Unit C illustrated in Figures 1 and 6 is of the same construction as the units A and B except that unit C is of adjustable width. In more detail, as best shown in Figure 6, the side wall I2a of unit C is formed by a U-shaped beam member, just as is the case with the corresponding side wall members of units A and B. However, member I2a is not fixed to the cross beams 9 but, instead, is provided with spaced shoes III! which fit between the cross beams 9, the lower surface of member I2a resting on the upper surfaces of the members 9. Member I2a is therefore mounted for movement toward and from the other and fixed side wall I of unit C, with this movement guided by the shoes II'O. Member I2a is moved with respect to member ID by means of a spaced series of threaded shafts III rotatably mounted in fittings II 2 secured to the outer surface of member I2a, the outer and threaded ends of the threaded shafts extending through threaded collars I I3 fixed to a beam I I4 which extends lengthwise of the apparatus. Each threaded shaft III has a sprocket H5 secured thereto, as is also shown in Figure 2, and all of the sprockets are adapted to be simultaneously rotated by means of a sprocket chain I I6 which extends lengthwise of'the apparatus and is adapted to be driven by a sprocket wheel II I at one end of the apparatus. Sprocket III-"is fitted with an operating handle I.I.8. If wall member I2a is of substantial height, as illustrated in the drawings, the shafts III may be arranged in upper and lower groups, with the shaftsv in one'group threaded oppositely to the shafts in the other group and so that all may simultaneously impart the same movement to the wall member I2a by use of the single sprocket chain such as shown in Figure 2.

Referring to Figure 6, the ejector fingers a associated. with the movable wall I2a of unit C are mounted for transverse adjustment with respect to table H. This adjustability is accomplished' by having the lower mounting bracket I20 for the fingers fitted with keys I2I movable in keyways I22 in the table. The brackets I20 can besecured in adjusted position by means of nut and bolt arrangements, such as indicated at I23.

It will be apparent that base plates Illa of different widths will be used according to the spacing between the walls I2 and I2a of unit C. The cores and matrices used with the unit will also be of different widths, depending upon the adjustment for which the unit is set.

"The operation of the unit C in forming a precast element will be apparent from the above description of the operation of the unit A. The press element J provided with the apparatus will be of such width that it will cooperate with matrices of the greatest width which unit C can accommodate. Because press element J is movable transversely of the frame G, it readily can be centered with respect to unit C regardless of the width for which that unit is set. The track 56 for the transporting carrier L provided for the mold unit C will be centered with respect to the limit of expansion of that unit. Also, the carrier L for unit C will be of ample width to receive the widest structural units which can be produced thereon.

In the foregoing, the operation of the unit A has been discussed primarily in connection with the production of a relatively long precast wall course element such as disclosed in Figures 37 and 38, and it will be noted that the units B, C and FA can be operated to produce the same type of element. However, as is best indicated in Figure 4, the units A and B can be used to form other types of building elements. The same is true of the units C and FA. This manner of operation is discussed below.

Referring to Figure 4, this figure shows the unit A in top plan, the top matrix being omitted from the view so as to show two completed concrete elements E2 simultaneously formed by the unit. Figures 39 to 41 show a pair of completed elements E2 in perspective and, by considering those figures with Figure 4, it will be observed that element E2 is provided with pairs of interior cross webs m and longitudinal panels 28m and 29:: generally similar to those provided in the element EI of Figures 37 and 38. In addition, the elements E2 include ridges 38x on one surface and recesses 24x on an opposite surface, but extending the entire length of the longitudinal panels. However, the matrices 22a; and 36a (Figure 28) used to form the elements E2 are of such shape that, in conjunction with cores 32 and 34 and certain collapsible cores or spacers hereinafter described, the matrices 22a and 36a will so form the left-handelement of Figure 4 that one end I24 thereof (the left-hand end of Figure 4 and the end shown in Figure will not be provided with a cross web at its extreme end, though it will have a cross web I25x spaced somewhat inwardly of its extreme end. However, the opposite end (shown at the center of mold unit A in Figure 4 and also shown in Figure 39) has a cross web I253: spaced inwardly therefrom and also a projecting portion I26 to fit between the open end of an adjacent similar element E2 as shown in Figure 41.

In more detail, the lower matrix 22a used in Figure 4 has the same form as the portion of matrix 22 which appears between the dotted lines 22a of Figure 20, thereby lacking the cross webs 3!. Also, as shown in dotted lines at the right of Figure 20, it will include a cross web I25 similar in outline to the cross webs 36 of matrix 22 and projecting above its ridges 2 1,

In order to form certain recesses in structural element E2, as well as to enable two such elements to be formed in one mold unit, a collapsible core element of the type indicated in Figures 23 and 24 may be used.

Referring t the collapsible core element I38 illustrated in Figure 24, it comprises an outer or casing member I 3| including a closed end I32 and an open end I33. An inner member I34 fits in the open end I33 of member I3I, the two members being slidable with respect to each other. The side walls of casing member I31 are formed of thin sheet material in order that it will have substantially the same horizontal dimensions as the inner member I34.

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