US2926411A - Machine for making concrete pipes - Google Patents

Description

3 SheetS Shee-t 1 H. STEIRO MACHINE FOR MAKING CONCRETE PIPES March 1, 1960 Filed Au 19, 1957 Q Q Q Q Q I N VEN TOR. HHEB Y 5 75120 B Y W M W A 77'0/QN1FY5 March 1, 1960 H, sTElRO 2,926,411

MACHINE FOR MAKING CONCRETE PIPES Filed Aug. 19, 1957 3 Sheets-Sheet 2 IN VEN TOR.

A meev 5715/20 BY AT raw/av March 1, 1960' H. STEIRO MACHINE FOR MAKING CONCRETE PIPES Filed Afig. 19, 1957 3 Sheets-Sheet 3 IN V EN TOR. flflezv STE/ea WM 45M "nited States MACHINE FOR MAKING CONCRETE PIPES Harry Steiro, Madison, Wis. V Application August 19, 1957, Serial No. 678,894

1 Claim. (Cl. 25-30) This invention relates to machines for making concrete pipes.

It is known in this art to use vibrators in machlnes of this general type to settle the mix in the forms. These conventional machines, however, usually use a rather Wet is rotated bodily in the center of a cylindrical mold, and

packs the material toward the outer side of the pipe.

These packer shafts sometimes shift from their rotational path which results in'a weak pipe of uneven wall thickness. Furthermore, this process requires a well furnished plant and balanced and well graded mix. The abrasive reaction of the materials used causes considerable wear of the parts.

The tamped pipe process requires a less accurately balanced mix, but there is also considerable wear of parts involved in this process and maintainance of machinery is high.

The simple cast" pipe process requires least skill, but to get a satisfactory production rate, many form sets and considerable casting space is required. In many prior art devices in general, there is considerable waste of concrete by spilling when loading the molds or forming the pipe, and while the amount wasted per pipe is perhaps not great, this waste is considerable when thousands of pipes are involved.

According to the present invention, a machine for making pipe has been provided which can utilize a no slump concrete mix and obviates the above-mentioned difiiculties and shortcomings of the prior art devices.

It is a general object of the invention to provide a machine for making concrete pipes, in which the production rate is greatly increased over conventional machines by novel means for forming the pipe and stripping the molds therefrom. As well as greatly increasing the speed at which a pipe can be produced, the resulting pipe has strength and permeability characteristics which are superior to those produced by conventional means and very much in excess of those required by the American Society for Testing Materials.

In accordance with the present invention, a machine is provided which can successfully utilize an extremely dry mix of no-slump characteristics. As a result, the tiles formed by this machine can be handled as soon as they are formed with no time delay in the operation of the machine. Furthermore, the tiles formed on this machine have very uniform wall thickness which results in maximum strength of the tile. In addition, the tile is excepatent 2 tionally dense and has a very' low absorption characteristic.

The invention further provides a machine in which the core of the mold is stripped from the tile in one direction while the outer cylinder of the mold is stripped in the opposite direction. At the same time the tile is securely held in position on the forming table by end forming rings which also serve to accurately form and densify the upper ends of the pipe. A machine is thus provided which is very efficient in operation and produces concrete pipe of exceptional strength and absorption characteristics at a cost less than those produced by conventional means.

These and other objects and advantages will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings, in which:

Figure 1 is a perspective view of a machine made in accordance with the invention, showing the cores of the molds in the lowered position and the outer cylinders of the molds in the partially raised position;

Figure 2 is a view generally similar to Figure 1, but showing the pistons or cor'es in the raised position and the cylinders also in the raised position;

Figure?) is an elevational view of the machine, certain parts in section and broken away for the sake of clarity in the drawings;

Figure 4 is an enlarged, fragmentary view, in section, and showing the pistons or cores in the pipe forming position, the finished pipe in place'and the outer cylinder core being stripped from the pipe while the ring holds the pipe in place; and V Figure 5 is a plan view of-the'machine as shown in Figure 3, certain parts beingshown infsection, broken away and removed for the sake of clarity in the drawings.

In this particular art, the terms'concrete pipe and tile are used to designate a diiference in size of the product. For example, the small sizes, that is from 4 This invention has found particular utility in making the so-called tile which present additional ditficulties when attempted to be made with a relatively dry mix. However, use of the invention is not necessarily limited to any particular size of product. I

Referring more particularly to the drawings, the machine is generally elongated in a vertical direction. The base support structure of the machine includes the four corner legs 1% to the top of which is rigidly secured the stationaryplate 11 which forms a table or reference surface on which the pipe is formed and from which it is removed. This table top is located at a very convenient height to facilitate removal of the finished product. Two pairs of braces 12 and 13 are welded between the legs 10 intermediate-the height of the legs to form a rigid base support structure. Cross beams 14 are welded be.- tween braces 12 and are spaced a distance apart from each other and act as stop members to limit the downward movement of the cores as will appear.

A large coil spring 16 surrounds the lower end of each leg 10 and is welded thereto. A foot plate 17 is in turnv welded to the bottom of each spring. In this manner the vibrations set up in the machines are absorbed by the springs and prevented from being transmitted to the floor F. i

A vertically positioned, double acting hydraulic cylinder 19 is rigidly secured at each side of the base structure by means of the brackets 20 welded to the sides of plate 11 and also by the brackets 21 welded to the braces 13. A piston rod 22 extends outwardly and upwardly from the cylinder 19. Conduits 23, 24- are connected to the upper and lower ends, respectively, of the cylinder and through which fluid pressure is admitted for lowering and raising the piston rods 22.

Another double acting hydraulic cylinder 26 is located centrally beneath table 11, and as shown in Figure 3, is attached thereto as at 27. This cylinder has conduits 26a and 26b in fiuid communication with its upper and lower ends, respectively. A piston rod 28 extends downwardly from this cylinder and is attached atits lower end to the center of the plate 29.

Table 11 has four large apertures 30 extending therethrough which are spaced a distance apart from one another. A large hollow piston or core 31 is mounted within each aperture 30 for vertical sliding movement therein. The top of each core is closed by a cap 32 welded therein, and the top of the core or cylinder 30 has a beveled edge 33 (Figure 4) around its top end.

Each core 31 is rigidly secured to plate 29 by means of a plurality of rods 34 which are welded at their top ends at circumferentially spaced points to the cores 31 and which are secured at their lower ends in apertures in plate 29 by nuts 35. Thus the double acting cylinder 26 and piston 28 serve to forcibly raise the plate 29 and its cores to the position shown in Figure 2 preparatory to a tile making operation, and then withdraw the cores from the finished tile by lowering the cores to the position shown in Figure 1. The diameter of the cores is such so as to form a snug sliding fit with the aperture 30 in the table 11, thus preventing any mix from leaking from the annular chamber 36 formed between the inner mold 31 and the outer mold 51.

Extending upwardly from each corner of the table 11, and welded thereto, is a post 37. The upper ends of posts 37 are rigidly secured together by being welded to the top plate 38.

An outer cylinder mold unit 40 is slidably mounted on posts 37. for vertical movement between a raised position and a lowered or pipe forming position. The cylinder unit includes a plate 42 which has a tubular member 43 extending through apertures in each of its corners and which are welded therein. Members 43 are slidable on posts 37, and the cylinder mold unit is thus guided in its vertical movement. I

The upper ends of the piston rods 22 are connected to the brackets 44 on plate 42, and the cylinder unit 40 is thus moved in a vertical direction by the hydrau ic cylinder 19 and piston 22 at each side of the machine.

The plate 42 forms a feed tray into which the concrete mix is dumped. For this purpose, vertical tray sides 45, 46 and 47 are welded together and to plate 42, and a fourth side 48 is also provided which is slightly inclined in an outwardly direction to facilitate the dumping of mix into the tray. Thus the four walls 45-48 act to confine the material on the plate 42. V

The feed tray 42 has four large apertures 50in each of which is welded an outer mold cylinder 51 which extends downwardly from the plate tray 42. The cylinders 51 are all rigidly secured together by the short braces 52 welded therebetween. I e

The cylinder mold unit 40 also includes a vibrator 55 which is bolted to a plate 56 that is welded to one side of two of the cylinders 51. This vibrator is of the electric motor type having adjustable eccentric weights on its shaft. Other forms of driving power, pneumatic for example, may, of course, be used. The centrifugal forces produced by rotating these eccentric weights are transmitted to the entire cylinder mold unit to which the vibrator is attached. In the use of a particularly "dry mix as is used in making smaller sizes of pipe by this invention, it has been found that an external vibrator of relatively low frequency and high force or impact will give an etfect to actually place no-slump concrete in the forms, rather than merely segregage water and air from the concrete slush. Stated otherwise, conventional wet cast vibrators operate at a frequency in the general neighborhood of between 9000 and 15,000 frequency impulses per minute but without any appreciable impact, or have a maximum impact of 50 pounds. In contrast, the vibrators used in the machine of this invention, however, generate only approximately 3000 impulses of frequency but deliver up to 4000 pounds of impact.

The concrete forms above described efficiently conduct the vibrations generated, uniformly around the outside and inside of the pipe forms. The result is a high compressive, homogeneous structure, having high compressive strength and low absorption characteristics.

A head unit 58 is provided which is also adapted to move vertically on the corner posts as guides. This unit includes a plate 59 which has short tubular members 60 extending through each corner of the plate and which are slidably mounted on the corner posts. Four shafts 61 extend through the plate 59 and are welded thereto. These shafts also slidably extend through apertures in the top plate 38. The shafts are concentrically located with their respective cylinder mold 51 and have a bar 62 welded across their lower ends. A packer ring 63 is welded to the bar 62 and is adapted to enter the cylinder mold 51 as shown in Figure 4. The ring has a beveled surface 64 which provides a relief angle with the cylinder.

The head unit is held in the retracted or uppermost position as shown in Figure 3 by the manually operated latch means 66. A central shaft 67 is welded at its lower end to plate 59 and slidably extends through aperture 655 in top plate 38. The shaft has a notch 70 in its side into which the rod 71 is adapted to be inserted. The rod 71 is shiftably mounted in the two lugs 72 welded to the top side of plate 38. A spring 73 is slipped over rod 71 and bears between the outer lug 72 and a stop member 74 secured to the rod. The spring thus urges the rod into engagement with the shaft 67 to hold the head unit in the raised position. When it is desired to reease the latch means to manually lower the head unit, the lever 75 is pulled downwardly causing it to bear against the edge of plate 38. The lever is pivotally attached to the rod and thereby pulls the latter free of the notch 70.

The head unit is raised by the cylinder mold unit as the latter travels upwardly. More particularly, the upper ends of the cylinder unit tubes 43 abut against the lower ends of the head unit tubes 60 after the cylinder unit has been raised a predetermined amount, as will appear.

An eectric motor 77 drives a hydraulic pump 78 to which the conduits 23, 24, 26a and 26b are connected. Suitable control levers are provided to cause pressure fluid to be admitted to the ends of the double acting servo motors as desired.

Operation The various parts of the machine are positioned as follows preparatory to forming a pipe. Fluid is admitted to the lower end of cylinder 26 which causes its rod 23 to carry the cores 31 upwardly to the position shown in Figure 2. The cylinder unit 40 can be lowered to the position shown in Figure 3, and these movements of the core and outer cylinder molds can be effected simultaneously, if desired. The head unit remains latched in the position shown in Figure 3. The vibrator 55 is then started, and the relatively dry mix, which can be of the no slump type is dumped into the tray table 42. The volume of material needed is predetermined, but any excess remains in the tray for the next batch of pipes to be made. The mix flows into the annular chamber formed by the cores 31 and cylinders 51, the entire cylinder unit being thoroughly vibrated, causing the mix to rapidly shift around on the table 42 and flow between the inner and outer molds until the chambers are filled. This filling process takes only a few seconds to complete.

The head unit is unlatched and manually lowered into position. The rings 63 accurately seat between the inner and outer molds, and due to the weight of the head unit, compress the upper inch or so of the mix so as to insure uniform density for the entire tile length. The

rings also serve to accurately form the upper end of the tile T and give it a sharp and distinct edge.

Only about to seconds are needed for the vibration period during which time the relatively dry mix is formed into a pipe of very dense texture. The vibrator is then shut off.

The inner molds 31 and the outer molds 51 may then be stripped downwardly and upwardly, respectively, at the same time. Alternatively, either mold may be removed before the other. rise, the rings hold the tile T against the table 11, and as the cylinders clear the finished pipes in their upward travel, the cylinder unit 40 picks up the head unit by contact with the tubes 60 as before mentioned, and raises In either event, as the cylinders the head unit to the uppermost position where it is automatically latched in place.

The four finished pipes are then completely exposed and can be removed from the table either manually or by a conveyor means (not shown). The pipes, while they are still wet and fragile, can be removed as soon as theyare formed.

The various parts of this machine are so guided in their movement that a pipe is formed which has very accurately dimensioned walls of uniform thickness. Good control of wall thickness is assured because both mold positions are always fixed.

This invention contemplates a machine capable of making only one pipe or any number at one time.

Products of the general type contemplated to be made by this invention must meet certain strength, permeability and other requirements. For example, the American Society for Testing Materials requires a strength of at least 1650 pounds per linear foot for a six inch tile-and using the sand bearing method of testing. Tile made in accordance with this invention have withstood loads of 2670 pounds per linear foot before fracture.

The industry considers a permeability of 8% to be good, that is, the product will absorb moisture of only 8% of its weight. chine tests at 6.47% using a mix consisting of three sacks of type III cement, 1200 pounds of sand and 750 pounds of pea gravel.

In hydrostatic tests, sixinch tile made on this machine withstood 120 p.s.i. without signs of leakage or fracture, while conventional practice accepts a hydrostatic test result of'30 p.s.i.

Products made in accordance with this invention require less cement in the mix and, therefore, not only The dense tile formed by this ma-' have much better strength and permeability characteristics, but are also more economical to produce from labor and material standpoints.

Various modes of carrying out the invention are contemplated as being within the scope of the following claim particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim: i

A machine for making concrete pipe from a no-slump mixcomprising, a vertically elongated support structure including a table on which pipes are to be formed, said table having an aperture therethrough, an outer cylindrical mold unit shiftably mounted on said structure between a position on said table and an elevated position, said unit having a cylindrical outer mold, an inner core mold mounted on said structure and to slide upwardly through said aperture to fit within said outer mold so as to form an annular chamber therebetween into which concrete mix may be poured, a head unit including ring means, said head unit mounted on said structure and shiftable between a pipe hold-down position and an elevated position, vibrator means connected with one of said molds for settling said mix in said chamber to form a densified concrete pipe, hydraulic means to shift said outer mold unit to said elevated position to thereby strip it from said pipe, said head unit and said outer cylindrical mold unit each having a member which abut with one another when said outer mold unit is elevated and at least substantially stripped from the pipe to thereby elevate said head unit from its pipe hold-down position by continued upward movement of said cylindrical mold unit, and hydraulic means to shift said core mold axially downwardly to strip it from said pipe, said hydraulic means adapted to strip the pipe immediatelyafter said mix has been vibrated and prior to the removal of said pipe from said table.

References Cited in the file of this patent UNITED STATES PATENTS 777,086 Emery Dec. 13, 1904 1,258,237 Monroe Mar. 5, 1918 1,433,204 Hodges Oct. 24, 1922 1,774,977 Jackson Sept. 2, 1930 1,787,449 Jackson Jan. 6, 1931 2,296,018 Boyle Sept. 15, 1942 Y FOREIGN PATENTS 1,108,795 France Sept. 14, 1955

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