US3060542A

US3060542A - Method of producing concrete block

Info

Publication number: US3060542A
Application number: US64920A
Authority: US
Inventors: Ferdinand C Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-10-25
Filing date: 1960-10-25
Publication date: 1962-10-30
Anticipated expiration: 1979-10-30

Description

Oct. 30, 1962 F. c. MARTIN 3,060,542

METHOD OF PRODUCING CONCRETE BLOCK Filed Oct. 25, 1960 2 Sheets-Sheet 1 22 I I n filming I! n Hiilh.

INVENTOR.

FERDINAND c. MARTIN ATTOR N EY Oct. 30, 1962 c, MARTIN 3,060,542

METHOD OF PRODUCING CONCRETE BLOCK Filed 001:. 25, 1960 2 Sheets-Sheet 2 INVENTOR. FERDINAND c. MARTlN ATTOR United States Patent 3,060,542 METHOD OF PRGDUCENG CONCRETE BLOCK Ferdinand C. Martin, 3575 W. Clarendon, Phoenix, Ariz. Filed Get. 25, 1960, Ser. No. 64,920 4 Claims. (Ci. 2.5154) My invention relates to an improved method of producing a concrete block. It relates more in particular to an improved method for producing a concrete block of the type known in the art as a slump block but having the feature that at least one face of the block to which plaster or the like is normally attached has a regular configuration and may optionally comprise a different material than the main portion of the block.

Concrete blocks have been made for a large number of years. A common method used to produce them in early stages was to tamp a relatively dry concrete mix into a mold, the bottom of which comprised a pallet and the sides of which were gated so that they could be dropped away from the completely cast block to permit its removal on the pallet. While this method of producing concrete blocks permitted production of non-planar finished faces, it had the disadvantage that the method involved the use of a relatively large amount of labor with attendant cost. In modern practice concrete blocks are formed by use of fully automatic or semi-automatic equipment, employing a relatively dry mix and are conventionally projected from the molds by direct vertical pressure so that the side faces are planar and relatively rough. While blocks produced in this manner are relatively inexpensive and may have very desirable structural characteristics, they make an uninteresting side wall from an architectural standpoint; and when used normally require an exterior finish.

To improve concrete blocks, particularly from an architectural standpoint, the so-called slump block has been developed in relatively recent years and has gone into somewhat general, if specialized, use. Such blocks can normally be produced by means of available fully automatic or semi-automatic forming equipment by first forming them in a mold somewhat deeper than the mold employed for conventional concrete blocks, and a mold deeper than the final vertical dimension of the block, and after being formed and ejected from the mold they are compressed vertically between top and bottom surfaces, normally by hydraulic pressure. The block resulting from the final step of the process, commonly called the slumping step, has the same vertical dimensions as the conventional concrete block which it would replace, but the sides become slumped and take on an irregular random shape, so that the faces of no two blocks are exactly identical. The slump block of the prior art, however, has a disadvantage in that all vertical surfaces have been the same characteristic of irregular random shape, and the rear surface of a wall made from such blocks is highly irregular. This kind of irregular surface can be used for direct application of plaster, although the plaster coat will be very non-uniform in thickness and a good finish is extremely difficult and costly to obtain. In modern building construction, however, it is a common practice to furr out the plaster or wall board by means of vertical strips. Tht plaster and wall are thereby separated, with resulting advantage from an insulation and other standpoints by the thickness of the strips used in the furring operation. Because of the uneven character of the slump blocks of the prior art, uniform application of furring strips is exceedingly difficult. The result is that slump blocks, although presenting certain very definite advantages from an architectural standpoint over the conventional flat sided concrete block, have not come into such general use as their finished appearance would warrant.

Accordingly, a principal object of the present invention is the provision of an improved method for producing a concrete block having both the advantages of a slump block and the advantages of the usual fiat faced concrete block of the prior art.

Still another object is the provision of a method for producing a slump block in which the random irregular shape characteristic of such block is confined to surfaces which are not ordinarily finished by the application of plaster or the like.

A further object of the invention is the provision of an improved method for producing a concrete building block.

A still further object is the provision of an improved method for producing a slump block or the like in which one vertical face of the block is finished smooth and optionally of a different material than the remaining portion of the block.

Other specific objects and features of the invention will be apparent from the following detailed description taken with the accompanying drawings, wherein FIG. 1 is a perspective view showing the first stage in constructing an improved slump block in accordance with the present invention;

FIG. 2 is an end View of the partly finished block as illustrated in FIG. 1 and also indicates schematically the final step in its production;

FIG. 3 is a view similar to FIG. 2 but showing the final step in the production of the block;

FIG. 4 is a perspective view similar to FIG. 1 but showing the completed block;

FIG. 5 is a view similar to FIG. 1 but showing a modified form of block just prior to its final processing stage;

FIG. 6 shows still another manner of producing the block;

FIG. 7 shows the completed block resulting from further treatment of the FIG. 6 blank, and

FIG. 8 is a fragmentary front perspective view showing the structure of a typical finished block.

In the general practice of my invention I first mold a blank for slumping, as in the prior art method, except that at least one longitudinal wall is molded to the same vertical height which will be characteristic of the final block after slumping. The front wall, and optionally at least a portion of the end walls of the block, are first molded with a vertical dimension greater than the final dimension, so that when the slumping step is performed only the front face and optionally the end faces of the block will take on an irregular random exterior configuration, leaving the rear face of the block planar and in vertical relation with both the top and bottom faces.

In producing the slump block of the present invention, conventional molding equipment may be employed, modifying the same, particularly the mold, only sufficiently to produce the modified blank which is subjected to the slumping or vertical pressure step. All such equipment is provided with means for vibrating the mold so that the mold becomes entirely filled with the concrete mix employed and all excess concrete is removed from above the mold so that the mold cavity is exactly filled. In the semi-automatic equipment the bottom face of the mold is normally movable, and the entire mold is turned over and the bottom of the mold moved vertically to extrude the finished cast block. When the block is slumped, the mold is designed so that the movable bottom area continues its vertical movement after ejection and performs the slumping operation by pressing the removed concrete casting down to the required vertical dimension. In the fully automatic type machine, the wet concrete casting is normally ejected without turning the mold over, and when u a slump block is made a separate pressure plate descends to apply vertical slumping pressure to the wet block. It does not appear necessary to an understanding of the present invention to illustrate the particular arrangement of equipment commonly employed to form concrete blocks. I have, however, indicated in the drawings, as will be pointed out, the separate pressure plate commonly used on the fully automatic type equipment. It should be understood of course however, that the invention is not limited to the particular type of machinery employed. In FIGS. 1 through 4 of the drawings I illustrate the method of producing the improved slump block of the present invention and show a finished block resulting from the method. The blank shown in FIG. 1 is produced by means of any suitable mold using any of the available equipment. The blank has a front wall 10,

end walls

11 and 12, rear wall 13 and the usual center web 14, leaving

usual air spaces

16 and 17 common to one type of building block. It will be noted that the front wall 10 has a substantially greater vertical dimension than the

side walls

11 and 12 and the rear wall 13. These latter are molded to the same vertical dimension which the final block will have. The difference in vertical dimension between the front wall 10 and the remaining portions of the blank shown in FIG. 1 is determined by the amount of slumping desired. A good rule of thumb to produce a nice appearing block is to make the vertical dimension of the front wall 10 one inch greater than the remaining portion of the blank. A common block of the type shown, for example, has an overall length of about 15 /2 inches, a width of about 7 /4 inches and a height of about 3% inches. When producing such a block the vertical dimension of the front wall 10 may optionally be, for example, about 4 /s inches. It will be noted also that a recess 18 is also formed between the front wall and the contiguous end walls and web 14. This is to provide for the ready and uniform flow of the concrete during the slumping operation.

The blank shown in FIG. 1, as already stated, can be produced on any usual type of equipment employing a suitable mold with of course the commonly used vibration to assure filling out of the mold and proper setting up of the aggregate. Since, however, the aggregate is at least partly deformed during the slumping operation it is desirable that the cement used contain an adequate amount of plasticiser to permit free flow. A suitable cement is readily obtainable from many sources and is commonly sold as plastic cement. The aggregate used in producing the block of my invention may be substantially identical with the aggregate used in conventional concrete I blocks but the amount of cement in the matrix and the amount of water are also somewhat increased so that a softer, potentially somewhat higher strength material is used. As an example, if a specification should call for a final compressive strength of 1,500 pounds per square inch I would employ a mix which theoretically would yield a final compressive strength of about 2,000 pounds per square inch. If the mold producing the blank shown in FIG. 1 is orientated in the same position as the blank shown in FIG. 1, it is of course necessary that the wiping action at the top of the mold remove the excessive material differentially, leaving the front wall 10 at the elevation shown, and the remaining portion of the block at a uniform lower elevation. The blank, however, may be formed in a mold reversed with respect to FIG. 1, in which case the blank shown in FIG. 1 can be inverted as it is removed from the mold. In any event, the blank shown in FIG. 1 is supported on a suitable base 21 as shown in FIG. 2 as it is removed from the mold, and a top plate 22 brought down under suitable pressure to the position shown in FIG. 3. It should be noted that as the pressure plate 22 moves downwardly it stops at the very top edge of that portion of the blank defined as the end walls and the back wall, but in its movement it compresses and slumps the front wall 10 to produce a front wall 10' having a slumped front face of random irregular shape, but having the same vertical height as the remaining portion of the block. The recess 18 is filled by the flowing of the wet concrete so that the

end walls

11 and 12 are imperforate and of conventional shape, depending upon the amount of slumping action there may be from bulging of part of the face of the

end walls

11 or 12 or the web wall 14, but in no event is the rear Wall 13 disturbed in any way. In this connection it should be noted that while the blank shown in FIG. 1 is plastic enough to permit its deformation and slumping action described, there should still be enough form retaining characteristic so that the remaining portion of the block will not slump merely through its own weight. For this reason, normally the base 21 will comprise a pallet holding, for example, two blocks on which the blocks may be removed for final setting and curing.

In the form of the invention shown in FIG. 5, I produce a blank identical with that shown in FIG. 1 except that a portion of the end walls is also made higher than the remaining portion of the blank so that slumping will not be confined to the front face of the block, but also extend to the ends. For convenience and to shorten the description, I have applied to FIG. 5 the same reference characters used in FIG. 1 with, however, the numeral 1 as a prefix to indicate modification. When a blank such as shown in FIG. 5 is subjected to the slumping step as shown in FIGS. 2 and 3, the outside face of the rear wall 113 will remain planar and retain its original configuration, but the slumping will be extended to the end walls as already indicated. There are several reasons why slumping of the end walls may be indicated such, for example, as instances where the end wall becomes an exterior surface as at a corner. This slumping may of course be confined to only one end wall if desired.

In FIG. 6 I show a modification in which I have also applied the same reference characters used in FIG. 1 with, however, the prefix 2 to indicate modification. In this form of the invention, however, the rear wall 213 is pre-formed preferably of a different material than the remaining portions of the block. Suitable means such as tongues 220 are provided on the pre-formed rear wall 213 so that when the remaining portion of the block is cast around them a rigid, unitary body will result. Preferably the rear wall 213 is formed of a suitable insulating material which may have its outside face treated to provide a permanent finish if desired.

My invention is not concerned with the particular manner of applying such a surface finish nor with the particular type of insulating material employed. Any of the conventional finishes and available insulating materials of adequate strength may be used. In this connection, it may be noted that with the remaining portion of the block constructed and laid to carry the load, the wall 213 may have substantially less compressive strength than would normally be required in a load-bearing wall. Among the materials which may be used successfully for the prefabricated inside wall 213 are molded cellulosic materials formed, for example, from wood, cork, begasse, paper pulp, ligno-cellulose and the like. Molded inorganic insulating material and mixturese may of course also be used. I may, for example, employ plastic or special cements which have been rendered porous by entraining air or gas with them. I have found, for example, that a porous, cement-type material sold by Borg-Warner and Company under the name Betocel is satisfactory.

The manner of forming the blank shown in FIG. 6 may be substantially identical with that described for forming the blanks shown in FIG. 1, except that the pre-formed rear wall 213 is first inserted into the mold and the wet concrete mixture poured and vibrated around it. After employing the final pressure step as, for example, in the manner indicated in FIGS. 2 and 3, a final block is produced having, for example, the general configuration shown in FIG. 7. The front wall 210 is slumped as in the previously described method and the overall height of the block is uniform with top and bottom faces planar and parallel to each other.

In FIG. 8 I show an illustrative view of a typical finished block produced in accordance with the present invention. This particular block does not show a separate rear wall as illustrated in FIG. 7, it being understood, however, that in all other respects the configuration of the block of FIG. 7 would be substantially identical with that shown in FIG. 8. In FIG. 8 it can be seen that the front face of the block has random irregularities produced by the slumping action, but that the top and bottom faces as well as the rear face are absolutely flat and uniform. The end faces may either be flat or slumped as desired, but in no case will slumping of the end faces produce any deleterious disfiguration of the plane faces of the top, bottom and rear exterior surfaces. This produces a block which can readily be laid with great accuracy and with a minimum expenditure of labor, leaving a perfectly flat interior wall surface which can be easily and inexpensively furred out for the conventional plaster finish. It should be noted that generally speaking, irregularities at the end of the block if not pronounced, will not have any appreciable effect in increasing the block layers time but on the contrary will sometimes have a certain amount of advantage in producing a stronger wall.

In the drawings I have shown a specific form of block and have described it as illustratively about 15 /2 inches long, about 7% inches wide and 3 /8 inches high. This type of block is conventionally referred to as a modular 8 by 4 by 16 inch block. It will be understood that when the block as shown in FIG. 1 or FIG. '5 is slumped there will be some change in some of the overall dimensions and this change will depend upon the amount of material which is displaced in the slumping operation. Illustratively, if a blank as shown in FIG. 1 is inches long it may be extended to approximately 15% inches overall if there is a one inch difference between the height of the front wall and the height of the rear wall. Similarly, the width may be extended from 7% inches to approximately 7% inches. These measurements are taken at the center of the block in each direction and at the top face, it being understood that no specific measurement can be made of the random front face or end faces where the greatest slumping action is manifest.

Those skilled in the art should also note that while for purposes of illustration I have shown a so-called 16 inch concrete block, the present invention may be practiced to produce any of the usual shapes and sizes of concrete blocks employed in the industry. For example, straight facing blocks and half blocks for corners may be produced to match the 16 inch blocks. Also, the blocks may be made in various widths and lengths and heights to secure special design effects or for special types of construction, while still employing the features of the present invention.

The terms employed in the specification and claims including the words slump and slumped are used in the common sense in which such words are used in the industry to which the present invention relates. Such words as front, bottom, rear and the like are used in an identifying sense throughout and not in a limiting or restrictive sense, except insofar as the context may so indicate. The scope of the invention, therefore, is not indicated by limited example in the drawings and specification, but is defined in the claims.

I claim:

1. A method of producing an improved slump block having front, rear and end walls with at least one exterior planar face which comprises first molding an intermediate blank having one exterior wall with the same vertical height as the desired completed block and an opposite wall of greater height than the first mentioned wall, ejecting said blank from it's mold, and then compressing the said blank vertically to the same height as the first mentioned wall to slump the second mentioned wall to random irregular exterior shape while leaving the first mentioned wall undisturbed.

2. A method as defined in claim 1 wherein at least a portion of end walls connecting said first and second mentioned walls are also initially formed higher than the first mentioned walls and are themselves slumped by the said compressing step of the method.

3. A method as defined in claim 1 wherein a recess is formed between the second mentioned wall and end walls during the first described blanking step, said recesses being filled by slumped material during the slumping step.

4. The method of producing an improved slump block which comprises preforming a rear wall therefor having the identical height and length desired in the finished block and with attaching means forming a part thereof, inserting said form'in a mold and casting wet concrete forming the balance of the block with said attaching means imbedded in said concrete, at least the front wall formed by the concrete being of greater height than the preformed rear wall, removing the entire block from the mold, and applying vertical pressure to the concrete while wet to reduce it to the height of the rear block and produce a slumped face of randomly irregular outline on at least the outside surface of the front block face.

References Cited in the file of this patent UNITED STATES PATENTS 1,118,681 Reagan Nov. 24, 1914 1,570,595 Stevens Jan. 19, 1926 1,879,841 Caswell et al. Sept. 27, 1932 2,288,559 Ward June 30, 1942 2,689,381 Terriere Sept. 21, 1954 2,708,783 Ripley May 24, 1955