US 3922124 A
A machine for casting concrete piles in sliding molds brought forward along a string of concrete material laid out at the front end of the mold which mold shapes the concrete material to the contour of a pile and compresses the string of concrete giving the concrete material its final dimensions while densifying the material.
Description (OCR text may contain errors)
United States Patent 1 Bjorhaag Nov. 25, 1975 1 1 SLIDING MOULD FOR CONCRETE PILES INCLUDING SLIPFORM AND ROLLERS  Inventor: Georg Bjorhaag, Karl bergsvagen 21, 662 O0 Amal, Sweden  Filed: Aug. 8, 1972  Appl. No.: 278,711
 Foreign Application Priority Data Aug. 12, 1971 Sweden 10272/71  U.S. Cl. 425/64; 425/219; 425/432  Int. Cl. B2813 13/02  Field of Search 425/59, 62-65, 425/432, 218-219; 264/33, 34, 70, 71', 165,
 References Cited UNITED STATES PATENTS 2,842,036 7/1958 Overman 404/103 3,091,013 5/1963 Robinson 425/59 3,123,656 3/1964 Rochlin 425/294 3,217,375 11/1965 Kinward... 425/218 3,516,341 6/1970 Olsen 404/103 3,553,797 1/1971 Horton 425/113 3,608,012 10/1971 Jonell et a1. 425/432 Primary ExaminerRobert D. Baldwin Assistant Examiner.lohn McQuade Attorney, Agent, or FirmUlle C. Linton  ABSTRACT A machine for casting concrete piles in sliding molds brought forward along a string of concrete material laid out at the front end of the mold which mold shapes the concrete material to the contour of a pile and compresses the string of concrete giving the concrete material its final dimensions while densifying the material.
2 Claims, 8 Drawing Figures US. Patent Nov. 25, 1975 Sheet10f4 3,922,124
U.S. Patent Nov. 25, 1975 Sheet 2 of4 3,922,124
US. Patent Nov. 25, 1975 Sheet 3 of4 3,922,124
US. Patent N0v.25, 1975 Sheet4of4 3,922,124
SLIDING MOULD FOR CONCRETE FILES INCLUDING SLIPFORM AND ROLLERS The present invention relates to a machine for casting concrete piles in sliding molds.
For a long time it has been desirable to be able to cast concrete piles in sliding molds. Casting in a sliding mold is a very rational method which compared to casting in stationary molds can signify a considerable reduction of costs in the very casting work itself as well as in respect to the investment for the plant. However, herebefore it has been very difficult to maintain the high quality and strength required for concrete piles when casting in sliding molds. Particularly the cracks running crosswise with regard to the direction of travel of the sliding mold during its displacement is a feature which cannot be tolerated. On account of the great slenderness of the piles they have to be cast in a horizontal position in which it is not possible to get any pressure force in the molded material by the weight of the superposed material as is the case when casting buildings by the sliding mold method.
It is an object of the present invention to provide a machine for the casting of concrete piles in sliding molds, the finished product being concrete piles of the required high quality and strength. The object of the invention is reached by using the present machine.
In the accompanying drawing an embodiment of a machine in accordance with the invention is illustrated which now will be described with reference to the drawings and in connection therewith the method according to the invention will also be described. In the drawings:
FIG. 1 is a top view of the machine placed on a molding bed for casting of piles. This figure is on a smaller scale than the other figures which are all of the same scale,
FIG. 2 is a rear view of the machine as seen in the direction of the arrow II in FIG. 3,
FIG. 3 is a side elevational view of the machine,
FIG. 4 is a cross section through the machine along the line IVIV in Hg. 3,
FIG. 5 is a corresponding cross sectional view of the machine along the line V-V in FIG. 3,
FIG. 6 illustrates a part of the machine corresponding the cross sections IVIV and V-V,
FIG. 7 is a cross sectional view perpendicular to the one of the part illustrated in FIG. 6, and
FIG. 8 finally illustrates a part of the reinforcement of a pile in a cross section corresponding the section of FIg. 6.
In FIG. 1 the machine according to the invention is indicated at 1 and it is designed to be displaced along a molding bed 2 for the concrete piles. The molding bed 2 supports three molds 3 each one being for a bottom half of a concrete pile. Each half of a mold 3 is according to FIg. 2 comprised by a concrete bed 4 with a steel lining 5 which in the middle forms a semicicular lining 6 for the mold and at the sides travelling rails 7 for the machine 1. The molding bed 2 at each end terminates with a mounting means 8 in which the longitudinal reinforcements is clamped and which reinforcements shall be enclosed in the pile and which before the concrete material is poured shall be stretched along the molds 3.
As is evident from the side elevational view of FIG. 3 the machine is comprised by three consecutive sections in its travelling direction, viz. an input section 9 for the concrete material, a surface smoothening section 10 for producing the upper semicylindric surface of the pile rising above the lower mold and a compression section 11 for the final compression of the concrete material. The three sections 9, 10, 11 are kept together by longitudinally extending beams 12 and they can together perform a displacement movement along the mold 3 on the rail portions 7 of the same (compare FIG. 2).
Besides in FIG. 3 the section 9 is illustrated in cross section along the line IVIV in FIG. 4. According to the figures the section 9 comprises an outwards open concrete bin 13, in the bottom of which a feeding means 14, supplemented by a number of guiding plates 15, is located. The feeding means 14 comprises a number of feed screws 16 and feed wheel 17 for peripherically feeding in the concrete material by means of the screws 16. A number of driving motors 18 are mounted on the gable of the section 9 for the operation of the feeding means, said motors preferably being hydraulic motors. Below the feeding means 14 an additional number of guiding plates 19 are arranged which at least in part are provided with vibrators 20. For the support of the section there are a number of wheels 21. In FIG. 4 the earlier mentioned reinforcement 22 for the concrete pile to be produced and which is stretched in the mold 3 is shown. As is evident more in detail from FIG. 7 said reinforcement comprises longitudinally extending bars 23 and a reinforcement bar 24 spiral wound around them.
Besides in FIG. 3 the section 10 is shown in a cross sectional view in FIG. 5. This section substantially comprises an upper mold half 25 complementary to the mold 3 which upper mold half is divided in two symmetric parts which in between them are connected by means of resilient organs 26, so that the upper mold half 25 can be widened when passing over large lumps of aggregate in the concrete material. Each one of the parts of the upper mold 25 is provided with a number of vibrators 27.
The remaining section 11 is besides being shown in FIG. 3 also shown in a rear view II in FIG. 2. The section 11 exhibits as principal element for each mold three rollers 28, thus altogether nine rollers are provided which are journalled in a frame 29 ofv which the beams 12 form part of the assembly. Via their bearings the rollers 28 can be exposed to vibration forces from vibrators 30 and in addition to a permanent load from weights 31 mounted on the frame 29 which weights can be varied as to weight and distribution.
Each one of the rollers 28 exhibit cylindric steps shaped sidetracks 32 which are arranged to run on the rail parts 7 of the molds 3. Between the sidetracks 32 there is a middle portion 33, the cross sectional shape of which has been adapted to the desired shape of the upper half of the pile which as mentioned in the embodiment described by way of example is of half cylinder size. This contour of the rollers corresponds in shape as well as in location to the profile of the finished pile while on the other hand the upper mold part 25 is in a higher position that this contour, so that the concrete material here is given a certain oversize.
In FIGS. 6 and 7 special element 34 is shown which serves the purpose of lifting the reinforcement 22 during the travel of the machine forwards over the molding bed. The reinforcement 22 shall in a finished pile be enslightly above the surface of said lower mold half. In the case where the piles are of very long extension, the sag of the reinforcement can, however, be so great that it arrives in a position too close to the surface of the lower mould half 3. In order to avoid this, the element 34 can be attached to the machine 1 and take part in its movement. As is evident from FIGS. 6 and 7 said element comprises a U-shaped knife with the one of its edges moving in front of the machine during its travel given a taper, so that it can lift up the reinforcement 22 which then can rest on the inner surface of the elements 34.
In FIG. 8 an additional suitable device is shown which is connected with the reinforcement 22 of the pile. In order to lift the piles out of the lower molding halves after the sliding mold casting operation has taken place, they are suitably provided with protruding screw taps at each end. However, these screw taps would be an obstacle for the passage of the sections 10 and 11. Therefore, the screw taps, one of which is indicated at 35 in FIG. 8, are each one mounted on a spring yoke 36 having its end connected with the reinforcement 24. The spring yoke 36 as is shown in FIG. 8 can have the shape of a U turned upside down and exhibits sides curved inwards. By this arrangement the upper mold half and the roller 28 respectively can press down the screw tap 35 during their passage, with the spring yoke 36 by its sides exercising their bias in order to again push up the screw tap 35 to the desired position above the surface of the pile.
The machine illustrated and described can, of course, as to its details within the scope of the invention, be adapted to the prevailing conditions. Thus the upper mold half 25 and the rollers 28 as well as the lower mold half 3 can be given their cross sectional profile in accordance with the desired profile of the pile. In addition to round piles there are also square and hexagonal ones in common use. The molding beds 2 are generally arranged in batteries in parallel arrangement in between them, so that they can be served by one and the same machine which by means of a travelling crane is displaced between the different molding beds, it also being possible to serve them by individual machines. A concrete mixing station also belongs to the equipment of the plant, from which station the concrete by means of transportation means can be fed to the concrete bins 13 of the machines, and lifting means are likewise installed for the finished piles as well as storage facilities.
The sliding mold casting operation of the piles is carried out in the following manner:
The lower mold halves 3 are prepared first, so that the rails 7 and the mold surface 6 are clean and when desirable separating powder is added. Moreover, the reinforcement 22 shall be stretched. concrete material is now fed into the bin 13 of the machine 1 and the machine is brought in over the molding bed 2, thereby being hauled by a winch, or carried by a travelling crane or being provided with its own driving motors. During its travel the machine has the section 9 in front and when this section has arrived above the lower mold half 3 the feeder device 14 (FIG. 4) is started. During the operation of the feeder device 14 the wheels 17 feed in concrete material towards the screws 16 which feed down the same in the respective lower mold halves 3 under a certain pressure, so that a good filling of the mold is obtained. At the same time the guiding plates 19 are vibrated by the vibrators 20, whereby the concrete material is still more densified and air enclosures 4 are vented out. Moreover, the adherence of the concrete material to the guiding plates 19 is avoided.
Thus the section 9 leaves behind runs of concrete material in the lower mold halves 3. According to the progress of the section 10 it, when reaching such runs, smoothes them out at their top side by the upper mold part 25 thereby giving them a cylindrical shape. The mold part 25 is at the same time vibrated by means of the vibrators 27, whereby the concrete material is still more densified and is given a smooth top surface. The device 34 according to FIGS. 6 and 7 assures that the reinforcement 22 will be in the correct position in the pile to be cast in case its self tension should not be sufficient to maintain it in the proper position.
As has been mentioned earlier the section 10 leaves behind a run of concrete material which relative to the dimensions designed for the finished pile exhibits a certain oversize. In section 11 following after section 10 a downwards directed pressure is applied by the rollers 28 at the same time as vibration is taking place. The section 11 is subjected to such a load that it cannot lift up itself by said oversized dimension of the run. By simultaneously applied downpressing and vibration forces a strong densification of the concrete material is taking place, so that there is given the necessary density required for piles. By pressing out the surplus concrete material a certain compression is at the same time taking place in the longitudinal direction which serves the purpose to eradicate the cracks in the material which have a tendency to arise during the casting in sliding molds, especially when the casting operation is undertaken in the horizontal direction. Such cracks can absolutely not be tolerated in an element subjected to such high stresses as a concrete pile which is the reason that hitherto it has been very difficult or next to impossible to produce concrete piles by means of the sliding mold casting process.
The machine after having passed the section 11 leaves behind a cylindric, strongly compressed and densified string of concrete of the cylindrical shape designed for the finished pile. As mentioned, the pile can be made with alternative cross sections, but the casting methos is in principle the same one.
After the proper setting time in the molding beds 2 the piles are removed by lifting, by way of example being lifted in the screw taps 35 mentioned according to FIG. 8. After preparation of the lower mold halves new piles can now be' cast in them. During the operation of the machine it may be necessary to fill new quantities of concrete material in the bin 13 from time to time. This is suitably done by means of an overhead crane travelling above the molding beds.
1. Machine for casting concrete piles comprising a molding bed having a plurality of elongated open top lower mold halves, step shaped tracks on said molding bed extending longitudinally of and alongside the open tops of said lower mold halves, a concrete feeding bin having bottor'n outlets, means in said bin capable of feeding concrete under pressure through said bin openings, wheels supporting said bin and riding on said tracks with said bin openings each positioned above one of said open tops of said'lower mold halves, sliding mold halves each having an interior cross-section corresponding to, but larger than the interior cross-section of one of said lower mold halves, a frame, a plurality of rollers rotatably connected to said frame on an axis perpendicular to the longitudinal axis of said lower mold halves, each of said rollers having stepped shaped side peripheries each corresponding to and rolling on one of said tracks and a middle portion having a lateral peripheral configuration corresponding to and of the same size as the cross-sectional contour of the interior of its corresponding lower mold halve, vibrators connected to said rollers, weights connected to said rollers, and bars connecting said bin, said sliding mold halves and said frame in that order and with said sliding mold halves each positioned above the open top of one of said lower mold halves and series of said plurality of rollers with each said series having its rollers positioned of said lower mold halves interiors.