US2453223A - Method for making concrete building units - Google Patents

Description

Nov. 9, 1948. A. HENDERSON METHOD FOR MAKING CONCRETE BUILDING UNITS 2 Sheets-Sheet 1 Filed Oct. 1, 1946 l/l/I/l/IIIIIIIIIIII Nov. 9, 1948. A. HENDERSON 2,453,223

METHOD FOR MAKING CONCRETE BUILDING UNITS Filed Oct. 1, 1946 I 2 Sheets-Sheet 2 Patented Nov. 9, 1948 BUILDING Albert Henderson. Pittsburgh, Pa., assignor, by

mesne assignments, to The Cemenstone Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Application October 1, 1946, Serial No. 700,501

1 Claim. (Cl. 25-154) This invention relates to the manufacture of' precast concrete building units such as wall members having surfaces which are exposed in the finished building.

In my copend'ing application Serial No. 657,497, filed March 27, 1946, I have disclosed a mold for making concrete building members including spaced side walls resting on a base and adapted to be clamped together. It is an object of this present invention to provide an improved method of manufacture in order to produce units havin flawless surfaces as removed from the mold and to prevent damage thereto between manufacture and erection. v

In molding precast building units of concrete, holes are left in the outer surfaces as a result of the formation of bubbles, which seriously mar the appearance of the units. These holes cannot be repaired readily and remain as permanent defects in the surface. In addition, precast units are subject to cracking and breakage of their corners during shipment and handling. They also frequently become soiled or otherwise marred or discolored.

I have invented a novel method for making precast building units whereby the aforementioned objections are largely avoided. In a preferred practice, I cast the units in crates formed of suitable wooden members disposed in the mold to form a liner. T-he crate protects the units from breakage during handling. I sheath the mold side walls with an absorbent fabric such as bur-- lap or the like. This serves several purposes. It tends to absorb water from the member being molded and gives it a dense, hard surface. It also prevents the formation of bubbles and the holes resulting therefrom. The fabric serves as an outer coating to protect the units from soiling or discoloration so that when it is stripped off at the time of erection or after erection a perfect product with fresh, clean surfaces is available. Alternatively, the fabric may be left on the units to provide a wall finish. It provides a surface which is well adapted to receive paint or a finished coat of plaster.

A complete understanding of the invention may be obtained from the following detailed description which refers to the accompanying drawings, illustrating a preferred embodiment and practice. In the drawings,

Figure 1 is a partial transverse section through a mold for the casting of a plurality of concrete building units;

Figures 2, 3 and 4 are transverse sections through a series of pallets of various widths having sealing gasket strips along their edges;

Figure 5 is a section through one of the gaskets to enlarged scale;

Figure 6 is a horizontal section through an end wall for use with the mold in Figure 1;

Figure 7 is a sectional view taken on the plane of line VII-VII of Figure 6;

' Figure 8 is an end view of one of the wooden members forming the shipping crate disposed in thCi mold;

Figure 9 is a horizontal section through the crate showing the end .pieces and the bottom piece;

Figure 10 is a side elevation of a completed unit having its end and bottom edges protected by the members forming the crate and its sides sheathed in fabric;

Figure 11 is a transverse section taken along the line of XIXI of Figure 10;

Figure 12 is a view similar to Figure 10 showing a modified form of crate; v

Figure 13 is an endelevation thereof: and

Figure 14 is a partial transverse section through a storage and aging chamber.

Referring in detail to the drawings, and for the present to Figures 1 through 5, a mold for casting concrete units indicated generally at l0 comprises abase I I having spaced side walls l2, l3 and I4 resting thereon adapted to be secured together by any suitable means. The base -II has pipe coils.

I 5 embedded therein to provide for radiant heating of the mold. The walls i2, i3 and it are reinforced concrete slabs with their upper edges armored by channels Hi. It will be understood that the group of side wallsfillustrated at Figure 1 is duplicated in a. continuous series to the desired extent of the overall width of a complete gang mold. The wall l3 has transverse supporting angles 11 secured to the bottom thereof. 1-

beams l8 adjusted to the desired height by blocks.

i8a rest on the angles [1 and are adapted to support pallets on which the units are cast between the side walls. In the left-hand mold compart- I ment between the walls l3 and i4 I have shown a liner or crate including a wooden bottom member iii-and end members 20. These members have nails driven therethrough as at 2| adapted to become embedded in the unit to hold the crate thereon during shipment. When the unit is ready for erection, the crate members may be readily stripped 011?. The crate members have ribs 22 and grooves 23 adapted respectively to form grooves andtst-ongues in the side and end edgm of the ing concrete therebetween.

edges thereof. As shown more clearly in Figures 2 through 4, pallets like that shown at 24 are 5 provided in a variety of widths such as 8", 12" and 16". The sealing gaskets 25 are of rubber and have a'curved face 28 adapted to engage the mold side walls. When compressed the gasket face 26 flattens out forming a tight seal.

The gaskets have vacuum cups 26a spaced along their faces 26. When the gaskets are pressed against the side walls of the mold, these vacuum cups grip the mold wall and hold the. gasket tightly thereto. When the mold is opened up and the side walls moved slightly apart to permit the removal of the unit cast therebetween, the gaskets move with the mold walls, sliding on the plates 24 to the extent of the lateral movement of the side walls. This prevents dirt from accumulating in the joints between the pallets and the mold wall. The upper surface 21 of the gasket is adapted to form a bevel on the lower corner of the unit being cast. A groove 28 forming the gasket is adapted to accommodate the 25 edge of the plate 24.- The latter is provided with pins 29 at intervals therealong to engage the side walls and maintain proper spacing therebetween.

' The gasket has holes 30 formed therein to accommodate the pins 29.

The ends of the mold compartments are defined by end walls 3| shown in detail in Figures 6 and 7. Each end wall is a length of I-beam standing vertically on the pallet, the flanges 32 having gaskets 25 removably applied thereto. The web 5 23 of the. length Of I-beam is coped out as at 84. The width of the flanges, of course, is such that the' gaskets thereon make tight sealing engagement with the mold side walls.

In casting units in the apparatus described above, I apply a sheathing 35 of absorbent fabric such as burlap to the mold side walls before cast- Conveniently, the sheathing is applied before the bottom member IQ of the crate or the pallets 24 are put in place and the side walls clamped thereagainst. The fabric sheathing may be secured to the edges of the bottom and end crate members [9 and 20 as by tacking. The fabric is also secured to the upper edges of the mold side walls by any convenient means to prevent sagging. When the pallets such as shown at 24 are used, the fabric may be secured to the mold wall and used repeatedly, instead (at being removed with the units, and

remaining thereon as a protective cover. Instead of burlap, I may use other fabrics such as muslin, or a fabric woven from glass fiber. In any case, the material should be porous enough to absorb excess water and air from the concrete to prevent the formation of bubbles. 4 6 When the members are installed, the fabric sheathing may befstripped oil or it may be left permanently adhering thereto. In the latter case, it is composed of material of a suitable color to provide a decorative finish or is painted when installed. It may also serve as a base for a finish coat of plaster. In addition to the bubble formation, the absorption of. water by the fabric sheathing makes the concrete denser on the surface and prevents checking. The sheathing, of

' course, serves to protect the unit from soiling or being otherwise marred, and also insures proper curing since it holds a supply of water and prevents dehydration of the units at the surface. The'sheathing may .be applied to all four suro of installation.

- 4 faces of the unit. In

sheathing may be subjected to a spray of colored plastic or rubber-on leaving the mold, thereby sealing the unit against loss of moisture during curing. I v

Instead of casting the units vertically as shown in Figure l. I may provide a crate having a. fabric sheathing on one side and dispose the crate horizontally with the fabric side down, and cast the concrete in the crate and thereafter cover the upper surface unit with fabric sheathing. The fabric sheathing left on the units may be suitably waterproofed as desired. 1

Figures 8 and 9 show the details of the crate which serve to protect the edges of the units from breakage during shipment prior to installation.

Figures 10 and ll'show a .complete unit 36 with the crate members I! and 20 and the fabric sheathing l5 thereon. It will be apparent that a unit so made is already boxed and wrapped for shipment as it comes from the molds.

Figures 12 and 13 show a slight modified form of crate including, in addition to the bottom and end members l9 and 20, a pair of spaced top members 31. These members are shaped to form the tongue on the upper edge of the unit, and the space between the members affords room for the casting of the concrete. This construction.

0 obviously, provides a crate extending around all four edges of the unit. Rods 38 for reinforcing the unit may be assembled with the crate, the end members 20 of the crate having holes to receive the ends of the rods 38. The crate members thus serve in a reinforcing position and the rods to brace the crate members.

Figure 14 illustrates an enclosure for storing units as cast either during curing or until needed for erection. The enclosure comprises a base 39 having embedded heating coils 40 for radiant heating, side walls .4l and a cover 42 hinged to one of the side walls. The base 39 has a depression 48 providing a pool of water for humidifyins the interior of the enclosure. Precast units such as slabs 44 are stood on edge in spaced relation on sills 45 laid in the recess of 43. When the cover 42 is closed, grooves 46 therein accommodate the tongues on the upper edges of the members and serve to maintain them in properly spaced relation. 1

It will be apparent from the foregoing that the invention provides an apparatus and method for making concrete building unitshaving numerous advantages over the existing practice and equipment. The invention permits the manufacture of a unitwhich is already boxed and wrapped as it comes from the mold so that it is protected against damage or soiling. The crate enclosing the unit may readily be stripped off at the time The fabric sheathing may be stripped off orleft on if desired to provide a decorative surface, a base for paint or a finish plaster coat. The absorbent fabric sheathing also improves the quality of the product by avoiding holes resulting from formation of bubbles, and increasing the density of the concrete adjacent the surface. The fabric also tends to prevent cracking or checking of the concrete and is advantageous in the curing because it holds a supply of water to prevent dehydration by evaporation from the surface. The fabric may be removed from the unit afterit is erected onthe job so that the surface of the unit is kept free from job dirt.

The apparatus of my invention also has m this one, it constitutes a, bag for receiving the concrete as cast. The fabric portant advantages. The pallets and end walls are simple and inexpensive yet sturdy, durable and easily adjusted. The storage enclosure mainheated air aroundthe units which causes nonuniform hardenin'jg on opposite sides.

Although I have illustrated but a preferred practice of my invention and certain modifications, it will be understood that changes in the procedure and construction disclosed can be made without departing from the spirit of the invention or the scope" of the appended claim.

I claim:

In the art of making precast concrete building units, the steps'including positioning on a mold an open faced box with a flexible wrapper disposed across an open face of the box, casting a plastic cementitious mix within the box and against said wrapper to form a building unit and when the mix has hardened removing from the mold the assembly of building unit, box and wrapper so that the building unit as cast is already boxed and wrapped adapting it to be transported while protecting against soiling or discoloration the face thereof disposed' against the Number Name Date 248,722 Driscoll Oct. 25, 1881, 640,653 Guy Jan. 2, 1900 681,700 Himmelwright Sept. 3, 1901 775,588 Warden Nov. 22, 1904 916,796 Simpson Mar. 30, 1909 1,324,027 Block Dec. 9, 1919 1,525,797 Blum Feb. 10, 1925 1,554,586 Lake Sept. 22, 1925 1,684,624 Hayden Sept. 18, 1928 1,708,555 Smith Apr. 9, 1929 1,744,309 Henderson Jan. 21, 1930 2,007,063 Rolland July 2, 1935 2,040,732 Foster May 12, 1936 2,220,448 Henderson Nov. 5, 1940 2,294,556 Henderson Sept. 1, 1942 2,310,400 Crane et a1 Feb. 9, 1943 2,363,226

wrapper without necessitating wrapping after casting.

ALBERT HENDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Brund Nov. 21, 1944

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