Method For Making Facing Brick With Varied Color And Texture

Abstract

A process for making concrete brick which has a sufficiently smooth and attractively colored surface to be used as a facing or outside surface building unit. Colors are applied as fluid color mixes to a plurality of the vertical faces of the mold chambers in a block making machine prior to adding concrete mix thereto. Rapidly thereafter, concrete mix is added and the mold is vibrated to compact the mix and concurrently distribute over the surface of the material in the mold portions of the color mix to achieve a desired color effect. The color mix applied to the mold surface may be changed according to a predetermined pattern on each batch of such bricks.

Parent Case Text

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of my copending U.S. Pat. application Ser. No. 489,625 filed Sept. 23, 1965 now U.S. Pat. No. 3,425,105 issued Feb. 4, 1969.

Description

The field of art to which this invention pertains is a method of molding wherein the mold and its contents are vibrated and differing components are brought into association at a shaping surface and a method of mold coating for a concrete base and the product thereof.

The prior art teaches rapidly paced high-speed blockmaking machines, as U.S. Pat. No. 2,366,780 operating cycles of 10 to 15 seconds and slowly paced coating processes for coating concrete surfaces one at a time, as in U.S. Pat. No. 2,806,277. Such procedures have not provided an economically produced and yet attractive facing brick as desired by the market.

The rapidity and forcefulness of operation of a conventional concrete blockmaking machine operating at cycles of 10 to 15 seconds is used to repeatedly and continuously rapidly effect incorporation of a highly fluid liquid-solid mixture into a dry concrete mass by forming a layer, notwithstanding that it is temporary, of that liquid solid-mixture on vertical surfaces of a mold, quickly filling the mold with dry concrete mass and rapidly vibrating the mold and discharging the coated mass from the mold in continually repeated periods of about 10 to 15 seconds; the concrete bricks produced by the process of this disclosure have improved mechanical characteristics as well as attractive appearance. One embodiment of the product according to this disclosure has the general appearance of a clay brick that has undergone substantial aging.

Accordingly, one object of this invention is to produce a new and useful concrete brick, i.e., a brick that may be used for the exterior facing of a building but which is made of concrete. Another object of this invention is to provide a process for producing an improved concrete brick. Yet another object of this invention is to provide concrete facing brick with the colored components and the support components mutually interpenetrating at the surface of the bricks and the color components of the concrete being specifically distributed on the brick surface according to a variety of plans and effects.

FIG. 1 is a perspective view of the apparatus of this invention, comprising a conventional blockmaking apparatus operatively attached to a pigment slurry spray and control subassemblies to produce the product of this invention; the stamp subassembly 71 is here shown in its uppermost position;

FIG. 2 is, generally, a front perspective view of the zone 2 of the apparatus shown in FIG. 1; more particularly, this view shows the mold frame 50 and related parts of the block making apparatus as seen along the line of discharge from the center spray head 126;

FIG. 3 is a top and side oblique view of a single brick made according to this invention;

FIGS. 4, 5, 6, 7, 8, and 9 are respectively, views of the faces of the block shown in FIG. 3 along the direction of the arrows 4, 5, 6, 7, 8, and 9, respectively;

FIG. 10 is a diagrammatic perspective view of the main subassemblies of the apparatus shown in FIG. 1; this FIG. is a composite FIG.: it shows in dotted lines a pallet 85 in its position prior to when the feed drawer moves over the mold frame 50 and shows a pallet 86 in full lines in its position after the concrete bricks have been formed by vibration and are stripped from mold frame 50 and are ready for transfer to the discharge conveyor 89;

FIG. 11 is a microphotograph view of zone 11 of FIG. 5;

FIG. 12 shows a microphotographic view of zone 12 of FIG. 5; this is shown to the same scale as in FIG. 11;

FIG. 13 is an overall diagrammatic view of the spray sequence controller subassembly 150 showing the electrical apparatus elements and their connections for control of the sequence in which the spray subassemblies are actuated;

FIG. 14 is a diagrammatic representation of a spray timer control subassembly for feed and discharge of one of the spray subassemblies;

FIG. 15 is a diagrammatic showing of overall relations of the major subassemblies which perform the process steps of this invention; and

FIG. 16 is a portion of a brick wall produced with the bricks of this invention;

DESCRIPTION OF THE PREFERRED EMBODIMENT

The apparatus 16 according to this invention, to perform the process and provide the product of this invention comprises a blockmaking apparatus 17 in operative combination with a pigment slurry spraying subassembly 19.

The apparatus 17 is a standard blockmaking machine such as in U.S. Pat. No. 2,366,780. It comprises a bin and chute subassembly 20, a feed distributor subassembly 26, a motor and frame subassembly 21, a mold and vibrator subassembly 30, a stamp and stripper subassembly 32, and a pallet feed and conveyor subassembly 36.

The bin and chute subassembly 20 comprises a conventional bin 18 and, operatively connected thereto, a discharge chute therefor, 22. A slidable valve plate 24 is located at the bottom of the chute 22, seals it and provides for controlling the discharge of material therefrom. A mixer 265 feeds concrete mix 35 into the bin 18.

The feed distributor subassembly 26 comprises a movable feed drawer 25 and a movable cutoff plate subassembly 28. The drawer 25 is located below the chute 22 and separated therefrom by the valve plate 24. The feed drawer is moved between its rearmost or feed position shown in solid lines in FIG. 2 and FIG. 10, which is to the rear (as herein described) of the mold frame 50 and its forward discharge position, shown in dotted lines in FIG. 2, by its actuation subassembly 29.

The mold and vibrator subassembly 30 comprises a mold frame 50 with a plurality of like rectangular chambers therein such as 51, 52, 53, 54, 55, and 56. The mold frame is supported on a pallet as 85. The pallet 85 is supported on resilient pier members as 41 and 42. Frame 50 has a vibratory subassembly as 43 on each side thereof. Subassembly 43 comprises eccentric weight members as 44A and 44B firmly fixed on a shaft 45. The shaft 45 is rotatably mounted in bearings in mold ears 48 and 49 which ears are firmly attached to the mold frame 50. Each shaft as 45 is driven, as by pulley, 46, by motor as 61.

The motor and frame subassembly 21 comprises the blockmaking machine frame 66 mounted on the foundation 67, and mold vibration motors 61 and 62 mounted on the frame 66. The mold vibration motors 61 and 62 each drive a pulley, as 46, by a belt, as 47, between each motor and pulley. The motor 61 drives a pulley 46 on one side of the mold frame 50 and another similar drive wheel pulley serves to transmit power from the motor 62 to a vibration-generating subassembly similar to 43 on the other side of frame 50. The frame subassembly 66 is provided with a feed drawer motor and drive subassembly 68 which is operatively connected to the feed drawer actuation subassembly 29 (as described in U.S. Pat. No. 2,366,780).

The stamp and stripper subassembly 32 comprises a set of stamps as 71 through 76 which match and enter the chambers such as chambers 51 through 56 respectively in the frame 50. A stamp drive mechanism 69 is supported on frame 66 for the stamp subassembly 32 (as described in U.S. Pat. No. 2,366,780).

The conveyor subassembly 36 comprises the conveyor frame 80 on which are supported conventional conveyor chains 82 and 83 and pallets as 84, 85, 86, and 87. The conveyor feed portion 88 passes pallets as 84 and 85 to the supports, as 41 and 42 therefor below the mold frame 50. The pallets as 86 and 87 with the plastic bricks thereon move away from the frames 50 on the discharge portion 89 of the conveyor. Details of such conventional structures are given in U.S. Pat. No. 2,366,780.

The pigment slurry spray subassembly 19 comprises a slurry tank subassembly 92, a slurry pipe and valve subassembly 94 and a slurry flow and spray control subassembly 96.

The slurry tank subassembly comprises three similar tanks 101, 102, and 103 each of 55-gallon capacity and each is firmly supported on a tank support frame 104 at a level substantially higher than the mold frame subassembly 50. In the preferred embodiment the bottom of tanks 101, 102 and 103 are all at the same level and 20 feet above the top of mold frame 50. Each tank as 101, 102 and 103 is connected by its discharge line as 105, 106 and 107 at the bottom thereof to a one-way check valve 109, 110, 111, respectively.

The slurry pipe and valve subassembly 94 comprises check valves 109, 110, 111; metering conduits 113, 114, 115; vent lines 117, 118, 119; spray heads 125, 126, 127; vent line valves 135, 136, 137; discharge head valves 138, 139, 140; a compressed air reservoir tank 132; air manifold line 134; air inlet lines 121, 122, 123; and air discharge control valves 128, 129 and 130. The check valves 109, 110, 111 are respectively connected to the top portion of downwardly extending vertical spray metering conduits 113, 114 and 115 respectively. The top of conduits 113, 114 and 115 are respectively connected to the inlet portion of vent line valves 135, 136 and 137 respectively; the outlet ends of valves 135, 136 and 137 are operatively connected to the bottom portion of upwardly extending vent lines 117, 118 and 119. Lines 117, 118 and 119 extend to the height of the top of tanks 101, 102 and 103, valves 109, 110 and 111 are below valves 135, 136 and 137. Below the connection of valves 109, 110 and 111 thereto, each vertical spray metering conduit line as 113, 114 and 115 is operatively attached to an air inlet line, as 121, 122 and 123 respectively and, at its bottom end to a slurry discharge spray head, as 125, 126 and 127, respectively. The air inlet lines 121, 122 and 123 are provided with air discharge control valves 128, 129 and 130 respectively; and such valves control the air flow to the corresponding spray head for that line from the air reservoir tank 132 by air manifold line 134.

The tank 132 is operatively attached to a conventional air compressor 133 therefor, and its indicator controller 147.

The spray lines 113, 114 and 115 are rigid 1-inch O.D. steel pipes and at their lower end, adjacent the spray head therefor are provided with spray head valves 138, 139 and 140 respectively, which control the discharge from said lines 113, 114 and 115 through the spray heads therefor. The lines 113, 114 and 115 are firmly supported on frame 66 by a bracket 142 which is firmly attached to frame 66 and lines 113, 114 and 115. Thereby the heads 125, 126 and 127 are firmly supported to the front of the most forward extension of the feed subassembly 26 and above the top of the frame 50 and below the uppermost extension of the bottom of the stamp subassembly 71, as shown in FIGS. 1, 2 and 10. FIG. 2 is taken along a view of the mold frame 50 as seen along the axis of slurry discharge spray head 126. Each spray head as 125, 126 and 127 is aligned to direct slurry from tanks 101, 102 and 103 respectively in a stream or spray to initially strike the back faces (the faces to the rear) of mold frame 50 of all the mold cavities or chambers such as 51, 52, 53, 54, 55 and 56 of frame 50.

The slurry flow and spray control subassembly 96 comprises a spray sequence controller subassembly 150 and a spray timer controller subassembly 152. The subassembly 150 is operatively connected to and actuated by the stamp drive mechanism subassembly 69 and is operatively connected to and actuates one or all of the subassemblies of subassembly 152. Subassembly 152 is operatively connected to and actuates various valves of subassembly 94. The valves 138, 139, 140 and 128, 129 and 130 and 135, 136 and 137 are all actuated electromagnetically by relays therefor as below described for the valves of subassembly 153.

Subassembly 152 comprises a plurality of like individual spray subassembly timer control subassemblies 153, 154 and 155 for respectively the valves associated with each of the lines 113, 114 and 115 respectively. As these subassemblies 153, 154 and 155 are alike the description of subassembly 153 applies to the subassemblies 154 and 155.

The subassembly 150 comprises an actuator switch subassembly 160, step switch subassembly 162, sequence choice switches as 163 through 180 and distribution lines 253, 254 and 255 all operatively connected.

Switch subassembly 160 comprises (a) switch support bar 159 which is rigidly attached to frame 66 and firmly supported on foundation 67 and (b) a feeler switch subassembly 158. The subassembly 158 comprises a rigid casing 157 supported on bar 159. The casing supports a switch feeler arm 190 and a switch 191. Arm 190 is operatively attached to switch 191 and spring means keeps arm 190 in extended position whereby the switch 191 is normally open. Switch 191 is connected at one end or terminal to a power source 192 and at its other end or terminal is connected by the actuator line 161 to step switch 162. Arm 190 extends from casing 157; the arm 190 is actuated by contact with a link member, as 195, which is a part of the stamp drive mechanism 69. Arm 190 is moved by member 195 and actuates (closes) switch 191 at the time the stamp or pressure head subassembly 71 is raised to its uppermost position as in FIG. 1, because link 195 attached to subassembly 71 is then raised and strikes the arm 190: this striking and closing of switch 191 passes power from source 192 to electromagnetic drive piston 197 of step switch 162.

An arm 199 of piston 197 then turns step slave wheel 200 of step switch 162 one step in a predetermined sequence of spray compositions. The step switch control wheel 200 is firmly and operatively connected to and rotates rigid step switch shaft 202 about its axis and so actuates each of a set of eccentric sequential step switch plates as 203-209 also attached to that shaft.

Each step switch plate as 203-209 actuates one of a pair of normally open electrical switch contact points as 213-219 respectively. Points 213 only are shown in closed position in FIG. 13. One of each pair of points, as 213-219 is connected to power source 192 and the other of each pair is connected to the solenoid coil of a relay switch as 223-229 respectively. Each relay solenoid coil serves to actuate a relay switch, (as 230 and 231 for coils 223 and 224 respectively). Each such switch as 230 is operatively connected to one terminal of each of three switches as 163, 164 and 165.

Each switch 163, 164 and 165 is connected at its other terminal to lines 253, 254 and 255. Lines 253, 254 and 255 are each respectively connected to subassembly 153, 154 and 155.

Each relay as 223, 224, 225, 226, 227 and 228 is connected by three switches (163, 164, 165 for relay 223; 166, 167, 168 for relay 224; 169, 170, 171 for relay 225; 172, 173, 174 for relay 226; 175, 176, 177 for relay 227; 178, 179, 180 for relay 228) whereby each position of the step relay switch 162 may actuate any or all of the subassemblies 153, 154 or 155. FIG. 13 diagrammatically shows the relations of table I------------------------------------------------------------------------- --TABLE I Position No. Points Closed Switches Closed Subassembly 1 213 163 Actuated _________________________________________________________________________ _ 153 2 214 167 154 3 215 171 155 4 216 172 153 5 217 175 & 177 153 & 155 6 218 178, 179 & 180 153, 154 & 155 _________________________________________________________________________ _

In the preferred embodiment, switch 162 is a nine-position step switch and each closure of the switch 191 by movement of arm 195 of pressure head subassembly 71 sequentially brings one other plate of the step switch into operation, whereby a predetermined sequence of actuation of subassemblies 153, 154 and/or 155 and spray from tank 101 and/or tank 102 and/or tank 103 into the mold 50 is achieved.

Subassembly 153 comprises a first time delay subassembly 240, a second time delay subassembly 244, and electromagnetic solenoids 242, 243 and 245 actuating the pistons of valves 128 138 and 135 respectively. These are operatively connected as shown in FIG. 14. The representation of the electrically operated valves conforms in general to the Recommended Practices Committee of Instrument Society of America. Such solenoid-operated control valves are conventional (pages 260 and 258 of "Handbook of Measurement and Control," Instruments Publishing Co., 1951). The time delays are also conventional and may have a wiring diagram as shown in FIGS. 4-9, page 62, "Typical Electronic Timing Relay Circuit" and as discussed at pages 4-10 of "Maintenance Manual of Electronic Control", E. Miller, McGraw Hill Book Co., New York, 1949, or FIGS. 206 and 208 (pages 240-244) of "Electronics for Electricians and Radio Men," Coyne Electrical School, Chicago, 1945. The details of such conventional timers and solenoid valves are not the essence of this invention.

Time delay relay subassembly 240 has an adjustable control dial 247. This dial provides for adjustably setting and controlling the length of time of opening of valves 128 and 138 and the discharge from pipe 113. Time delay 244 has a similar adjustable control dial 248 to control the time of delay between closing of valves 128 and 138 and opening of valves 135 and discharge from line 113 and refill thereof from tank 101 after line 253 is activated by subassembly 150. Subassemblies 154 and 155 have similar or commercially identical time delay subassemblies to control the time of discharge from filling of lines 114 and 115 respectively with the liquid from tanks 102 and 103, respectively after lines 254 and 255, respectively are actuated by subassembly 150.

According to this invention, the components of the concrete (sand, gravel, cement and water) are stored at 261, 262, 263, and 264, respectively, blended in a mixer 265, and passed to bin 18. The surfaces of the cavities in the mold assembly 50 are covered with a layer of pigment slurry by the subassembly 19. The chambers as 51-56 of the mold are then filled with concrete mix agitated and compacted. The peripheral layer of pigment slurry is then distributed over and through the surface layer of the concrete block thus formed. The resulting coated bricks as 270 are then stripped from the mold and forwarded over the conveyor system 36 to a kiln as 277 whereat they are cured.

According to this invention, a standard concrete mix 16 for a concrete block such as set out at table II is fed into a mixer 265, there well mixed and thence to the bin 18. The concrete passes via chute and accumulates above the valve subassembly plate 24. It opens to pass a given volume of concrete to a distributor subassembly 26 which has a lower cutoff plate 28 provided therewith. A pallet 85 is moved to below the mold and held in contact therewith by piers as 41, 42. Subassembly 19 sprays and then the distributor subassembly 26 moves forward from the position shown in FIG. 10 to the dotted line position 27 shown in FIG. 2. Thereafter (during its operating cycle) the cutoff plate 28 is moved backward from the forward position of the distributor subassembly 26 and the concrete mix material therefor carried in the distributor or drawer subassembly 25 drops into the block-forming orifices of the mold subassembly 30. The distributor subassembly frame then moves backward to the position shown in FIG. 10 beneath chute 22.

When the feed drawer moves back to its original position it strikes off excess material from the top of the mold. A quantity of material adequate in amounts to make a commercial desirable block is left in the mold chambers but the top of this block is not completely packed. The mold is designed so that it is higher than the required height of the block. When the pressure head comes down and the vibrations continue the top of the block will be packed and smoothed out and thus completed. Although the vibration units as 43 have sufficient power to move the mold 50 through a larger amplitude than its actual operating amplitude, the jolting effect adequately packs the concrete in the mold and when the pressure head falls down upon the concrete material in the mold (which mold continues to vibrate) the top of the concrete material is rapidly packed and smoothed out. The pressure head or stamp subassembly 32 rests on the concrete material in the mold and progressively descends as the concrete becomes packed. The pressure head is limited so that the pressure head sinks only a predetermined amount into the mold and so forms blocks of universal height. Thereafter the pallet 85 is moved downward; the blocks in the mold follow the pallet and are stripped from the mold as the stamp subassembly 32 moves from its upper position shown in FIGS. 2 and 10 downward and pushes out the concrete bricks as 270 formed by the vibration onto the conveyor belt subassembly 36. The bricks are then passed to kilns as 277 whereat they are treated at 180.degree. F. for 4 hours; the temperature is then gradually raised at a substantially even rate to 360.degree. F. over a period of 2 hours and then held at 360.degree. F. for 5 hours. Following this 5 hour treatment the bricks are discharged.

The plastic masses 290 of compacted concrete mix produced by any of the procedures of table III, Parts A, B, and C, or the "antique brick" process herein described, may be separately treated in a conventional pressing apparatus 278 to provide rough surfaces on the future exterior surface of the brick by conventional mold or die machines and processes, e.g. as shown in U.S. Pat. Nos. 415,774 and 415,773 prior to passage of those plastic concrete brick masses to kiln 277.

The mold frame 50 is supported on the frame 66 in slots that permit the mold to vibrate in a vertical plane; the belts between pulleys 46 and the motor as 61 driving such pulley prevents motion forward and rearward. Each mold cavity as 51-56 is 81/4 inches deep, 21/4 inches wide and 35/8 inches long. The rear face of each chamber, as face 271 of chamber 56, forms the exterior or veneer face of each concrete brick formed as 270.

The tanks 101, 102, 103 are each provided with mixers therein and the mixers are driven by 1/3-H.P. electric motors to keep the slurry therein uniformly mixed.

The lines 113, 114 and 115 are each 4 feet long from junction of line 113 of such line with the air line 121, 122 and 123 to the inlet of their discharge valves 138, 139 and 140, respectively. All these pipes have a 1-inch outside diameter and 3/4-inch internal diameter and are made of rigid steel. Sprays 125, 126 and 127 are of the same size and shape.

The components of the apparatus 16 are arranged, as shown in FIG. 1 so that the operator at 260 may, while at a safe distance from the blockmaking machine 17 and spray subassembly 19 conveniently view the bricks on the discharge conveyor 89 produced by the apparatus 16 and adjust control dials as 247, 249 and 250 of subassemblies 153, 154 and 155 respectively for control of duration of time of discharge of liquid from lines 113, 114 and 115.

The size distribution of the aggregate used for the concrete brick is given as table II below.-------------------------------------------------- -------------------------TABLE II Sieve Size Gravel Sand Silica Total -1/2 100 100 -3/8 98 100 99.6 --4 mesh 20 97 81.6 -8 2 85 68.8 -16 11 1 73 59.5 -30 53 44.1 -50 18.6 17.9 -100 3.8 100 6.7 -200 0.66 1.8 89.5 5.4 Total weight 20.2% 76.0 3.8 _________________________________________________________________________ _

The percentage of cement (by weight for the concrete mix of table II is 10 percent (A.S.T.M. type I, physical and chemical properties in A.S.T.M. C-150-41).

The same cement is used in the Color Mixes of table III herebelow.

In regard to the spray subassembly action, at starting or zero time, subassembly 32 has finished its downward stripping motion and starts upward. About one-fourth second later, subassembly 32 has finished its upward motion, arm 195 moves arm 190 and closes switch 191 and actuates control subassemblies 150 and 152. When the solenoid controls as 242 and 243 open valves as 138 and 128 the pressure in the air compressor chamber 132 is applied against the liquid in line 113, valve 135 than being closed. Liquid in line 113 is then driven out of spray head 125. The spray head 125 discharges the liquid against all of the rearmost faces as 271 of the chamber as 56 in mold 50. The liquid stream so delivered is bounced back, in part, from such rear walls, and hits the front walls as 273 and sidewalls as 272 and 274 of each chamber. The thus-impinged slurry adheres to the walls so impinged upon. Subsequent addition of the material from the drawer subassembly 26 into the mold chamber cavities and vibration of such material, principally in a vertical direction, results in a relatively even distribution of the impinged liquid slurry over the surfaces of the compacted material. This distribution of slurry over the surfaces of the compacted material is limited by the quantity of liquid delivered to each chamber; when more slurry is added there will be a relatively even distribution over all the surfaces of the mold chambers, e.g. surfaces 271, 272, 273, and 274 of chamber 56; when the pressure in air tank reservoir 132 is high the stream of liquid will be bounced off more vigorously from the rear walls, as 271, to the front walls, as 273, of each chamber. When the volume of slurry delivered from a spray head as 125 to the mold chamber as 56 is increased there will be more coverage of all surfaces of the brick. When the pressure in air line 134 is kept at 40 p.s.i.g., as shown by indicator-controller 147 and one full second is allowed from discharge from each of the lines 113, 114 and 115, a full and even coating of all faces of the bricks as 270 formed is obtained. When lesser time, i.e., 0.3 second is allowed for slurry discharge from lines 113, the surfaces of the brick as 281, 282, 283, 284, 285 and 286 appear as diagrammatically shown in FIGS. 3-9. The composition of the spray is then as in table III, Part B, Color Mix 2 of Red Blend.

These bricks as 275 made by such process are not evenly colored throughout their entire surface; to the contrary, each surface as 281 of such brick has one portion as 287 that is a surface, which, to the naked eye, is as smooth as the outer surface of a conventional clay brick used for outside or finish or veneer purpose, while the remaining, lower portion 288 of that brick surface has an uneven appearance, as though the surface of such brick had worn or spalled slightly over the years. As such brick simulates an antique or used brick, such brick is referred to herein as "antique brick." It may be made with any color pigment such as brown, green or yellow or with any combination of colors as is done by the process taught in table III herebelow.

There is a slightly different appearance of each brick made in mold 50 at one time by this process when the surfaces of the brick are thus "starved" with an amount of slurry insufficient to cover the entire surface thereof. The surfaces 281, 282, 283, and 284 which extend from top (285) to bottom (286) surfaces are referred to herein as the longitudinal faces or surfaces of the brick. The surface 281 adjacent the rear mold surface, as 271 in mold chamber 56, is the one most completely covered by the color mix when the starvation mixture of the "antique brick" procedure is used.

The feed of concrete mixture to mold 50 begins after subassembly 17 spray has been completed, and usually takes about 2 to 3 full seconds; the striking of excess concrete mix takes about one half second. The finished vibrations to compact the mix takes about 4 seconds and is followed by upward motion of subassembly 32 by the stamp and stripper drive subassembly 69, motion of the arm 195 thereof attached to subassembly 32 and closure of the theretofore open switch 191 and the procedure of coating the mold with a spray from subassembly 19 is repeated. The exact times for each of these steps of operation of apparatus 17 are conventionally controlled.

In the preferred embodiment of this invention the switches as 163-180 of subassembly 150 are arranged as in table III, Part B, to connect the lines 253, 254 and 255 and color mixes in tanks 101, 102 and 103 to operate in the sequences there shown and with the compositions of pigment slurry in table III, Part A. FIG. 16 shows a section of wall made with concrete brick surfaced according to the ASPEN TONES procedure of this invention. Other procedures using the apparatus of the invention are also shown in table III (Parts A, B and C).

As each chamber in the mold 50 presents a somewhat different combination of surfaces to the spray, so there is a variation in the amount of slurry impinged upon surface of the rear face, as 271 in chamber 56, of each chamber in the mold 50. Each resultant brick as 275 therefore not only has a varied surface color and texture on each face thereof but also each brick in the batch has a surface color and texture different than the others in that same batch. This relationship occurs in the manufacture of "antique brick" as above described as well as in the processes performed according to the operations set out in table III herebelow. ##SPC1## ##SPC2## ##SPC3##

As shown in FIG. 16, the process of this invention not only provide that there is variation of surface color and texture on each exposed brick surface, but also there is variation of surface color between the bricks produced by the same process while utilizing conventional block making apparatus, as 17 and 277 and conventional block making materials (261, 262, 263, 264). Further still, by this invention the variations are readily made, e.g. by changing pattern of switches as 163-180 as shown in table III (parts A and B) as well as by changes in composition of the color mixes used in tanks 101, 102 and 103 (vide Table III, Part A). The intensity of coloration is readily varied by dials 247, 249, and 250. As shown in the procedures of table III, Parts A and B entitled "Yellow Blend" and "Red Blend" and "Brown Blend" the same color may be applied to all portions of the brick surfaces.

The characteristics of the ASPEN TONES concrete brick produced by the process of this invention are illustrated in test results from 10 samples shown in table IV, herebelow. ##SPC4##

(1) The parenthetic figure is the corresponding figure for grade SW Clay Facing Brick (A.S.T.M. C-216). By test A.S.T.M. designation C-55-64 percent, Tentative Specifications for Concrete Building Brick, the results were as follows:

The process of this invention producing ASPEN TONES produces 32 bricks, each 21/4inches .times. 35/8inches .times. 75/8inches per stroke of subassembly 32, and, on each 700 strokes uses a total of 30 gallons of slurry and 10 pounds cement and 15 pounds color per 20 gallons of water in the slurry for an overall average solids thickness of only about 3.3.pi. (or less as below calculations).

The square inches of surface per brick are: (35/8 .times. 75/8 .times. 2) + (75/8 .times. 21/4 .times. 2) + (35/8 .times. 21/4 .times. 2) = 106 sq. inches ##SPC5##Assuming for purpose of calculations a specific gravity of 3 for the average of 5 to 20 lbs of pigment (of specific gravity of 4 to 5) per 10 lbs of cement, the thickness of the cement and pigment layer is: ##SPC6##

As cement particles average over 5-10 .mu. in diameter (with an average surface area of 1,600 sq. cm./gram) the layer of cement and pigment formed by the liquid slurry from tank 101 102 and 103 is usually not complete. Nevertheless the coated surface portion as 287 of the bricks as 270 or 275 appears as smooth to the naked eye as does clay brick veneer facing. At about 8X magnification as shown in FIG. 11, zone 11 of FIG. 5 has some perforations, 291-301. The same magnification of area 12 in zone 288 of brick 275 on which surface area where there is no coating is shown for comparison in FIG. 12; such common concrete block surface appears rough to the naked eye. The "antique brick" process produces a gradation between the smooth portion concrete with a pigment-cement layer as 287 and the nonsmooth uncovered portions as 288 and zone 12 of FIG. 5.

Portland cement has a coefficient of thermal expansion of 5.9 .times. 10.sup.-.sup.6 inch/inch .degree.F. and concrete is normally accepted as having a coefficient of thermal expansion of 5.5 .times. 10.sup.-.sup.6 inch/inch .degree.F. (Concrete Manual by U.S. Department of Interior, Bureau of Reclamation, Sixth Edition, page 16; and Engineering Materials Handbook, Mantell, p. 23-24). However, the use of high-pressure steam curing or autoclaving as used in the process of this invention decreases the amount of cement needed in the mix and provides a unit of very low reactivity to moisture expansion.

The concrete mix may be reduced in cement content, according to this invention, to reduce the coefficient of thermal expansion to 2.9 .times. 10.sup.-.sup.6 (A.S.T.M. C-426). The surface of the concrete bricks produced by the operation of table III are also as smooth as clay brick to the naked eye and at 8X still appears fairly continuous and unbroken. The finely divided cement and pigment slurry here also does not, however, form a complete and unbroken surface and the expansion that such surface veneer does undergo does not accordingly provide severe stress to the more porous concrete meshwork therebelow because such surface is not in fact complete and the pores provide for stress relief. Therefore, this high cement content layer does not interfere with the low coefficient of thermal expansion of the mass of the concrete brick therebelow. The pore sizes are less than 0.015 inch in diameter and about 0.005 inch in diameter average.

Accordingly, the concrete bricks produced by the process of this invention present exterior surfaces that appear smooth and continuous to the naked eye but do not suffer any mechanical disadvantage from a relatively high cement content in their surface layer. There is no mechanical disadvantage due to the high thermal coefficient of expansion of the cement.(5.56 to 6 .times. 10.sup.-.sup.6 inch/inch .degree.F.) in the high cement content surface layer because the surface layer of cement and pigment, although complete to the naked eye (like a halftone or newspaper picture) is (like a newspaper picture formed of dots,) not complete and so does not interfere with the design factor of lower (as low as 2.9 .times. 10.sup.-.sup.6 inch/inch .degree.F.) coefficient of thermal expansion provided by the concrete mixes used in this invention. In the preferred embodiment of this invention the coefficient of thermal expansion of the bricks as 270 and 290 produced thereby is 3.3 .times. 10.sup.-.sup.6 to 4.0 .times. 10.sup.-.sup.6 inch/inch .degree.F., the same as clay brick (Engineering Materials Handbook, Mantell, p. 25-15).

While the operations have been here disclosed as making concrete bricks of a given size, the scope of the invention, of course, covers making concrete blocks colored as above described in regard to the process of table III whereby to provide a permanent and uniform coloration and surface texture to all of a group of such blocks notwithstanding any variations in the color of the concrete of which made, as well as to produce a variation of surface color on such blocks as above described in particular for bricks. This is accomplished by using a conventional block mold in lieu of the brick mold 50 above described.

Although in accordance with the provisions of the patent statutes, particular preferred embodiments of this invention have been described and the principles of the invention have described in the best mode in which it is now contemplated applying such principles, it will be understood that the operations, constructions and compositions shown and described are merely illustrative and that my invention is not limited thereto and, accordingly, alterations and modifications which readily suggest themselves to persons skilled in the art without departing from the true spirit of the disclosure hereinabove are intended to be included in the scope of the annexed claims.

Claims

1. In a process for making concrete bricks which process comprises a cycle of steps said cycle comprising the step of filling a chamber of a mold with concrete mix vibrating the mold and compacting the concrete mix therein to form a plastic mass, and removing the plastic mass from the mold, each said cycle being completed within 15 seconds, and curing the plastic mass, the improvement which comprises spraying the mold surfaces for a period of from 0.3 to 1.0 seconds with a fluid liquid slurry comprising cement and pigment prior to each filling of said chamber of said mold with said concrete mix and thereby distributing said liquid slurry over the surface of said plastic mass prior to the removal of each

2. Process as in claim 1 wherein the liquid slurry concurrently forms a layer over a plurality of the longitudinally extending surfaces of the

3. Process as in claim 1 wherein said longitudinally extending mold surfaces are vertical and are spaced apart a distance less than the

4. Process as in claim 1 wherein the fluid liquid slurry concurrently forms a layer over all of the longitudinally extending surfaces of the mold and is subsequently distributed over all longitudinally extending surfaces of

5. A process for repeatedly and concurrently making a plurality of concrete bricks of differing surface appearance which process comprises the cycle of steps of filling each of a plurality of vertically extending chambers in a mold with concrete mix, vibrating the mold and compacting the concrete mix in each of said chambers to form a plastic mass, removing each said plastic mass from the mold and thereafter curing each said plastic mass, said cycle of steps of filling, vibrating and compacting and removing being completed within 15 seconds, and which process comprises the process step of spraying the mold surfaces of each chamber for a period of 0.3 to 1.0 seconds with a first fluid liquid slurry comprising cement and a first pigment prior to each filling of each said chamber of said mold with said concrete mix and thereby distributing said liquid slurry over the surface of said plastic mass adjacent said mold and then repeating the above cycle while performing the said process step with a second slurry comprising cement and a second pigment and thereafter repeating the above cycle automatically with each of a series of different

6. Process as in claim 5 wherein the slurry is sprayed in the amount of 3/70 gallon of liquid per each 100 square inches of mold surface and each 20 gallons of said liquid contains 5 to 10 pounds of cement and 5 to 20 pounds of pigment.