Method and apparatus for casting concrete products

Abstract

A method and an apparatus for casting concrete products with a substantially horizontal slipform casting process, where concrete mass is fed under pressure through a restricted cross-section defining the product to be cast, wherein the upper surface of the restricted cross-section is formed of a plurality of sections, which sections are moved in back and forth trowelling motion in the casting direction, wherein the adjacent sections are moved at different phases and/or at different speeds.

Claims

1. A method for casting concrete products with a substantially horizontal slipform casting process, where a concrete mass is fed under pressure through a restricted cross-section defining the product to be cast, wherein an upper surface of the restricted cross-section is formed of a plurality of sections adjacent to each other and having a gap of a predefined size between each of said adjacent section in the casting direction, comprising moving said adjacent sections in a back and forth troweling motion in the casting direction to enhance a compaction of the casted product, wherein the adjacent sections are moved at one or more of: different phases and different speeds.

2. The method according to claim 1, wherein at least some of the adjacent sections of the upper surface of the restricted cross-section are arranged at an angle relative to each other.

3. The method according to claim 1, wherein the predefined size of the gap is in a range of 0.5-2 mm arranged between the adjacent sections of the upper surface of the restricted cross-section.

4. The method according to claim 1, wherein the adjacent sections of the upper surface of the restricted cross-section are arranged in a vertical orientation and a horizontal orientation in relation to a lower surface of the restricted cross-section.

5. The method according to claim 1, wherein the predefined size of the gap is in a range of 10-20 mm arranged between the adjacent sections of the upper surface of the restricted cross-section.

6. An apparatus for casting concrete products with a substantially horizontal slipform casting, which apparatus comprises a restricted cross-section defining the product to be cast, and at least one feedscrew for feeding a concrete mass under pressure to the restricted cross-section, wherein a upper surface of the restricted cross-section comprises a plurality of sections adjacent to each other and having a gap of a predefined size between each of said adjacent section in the casting direction, and the apparatus comprises at least one motor for moving the adjacent sections back and forth in trowelling motion in the casting direction to enhance a compaction of the casted product at one or more of: different phases and different speeds.

7. The apparatus according to claim 6, wherein the adjacent sections of the upper surface of the restricted cross-section are arranged at an angle relative to each other.

8. The apparatus according to claim 6, wherein the predefined gap is a gap in a range of 0.5-2 mm arranged between the adjacent sections of the upper surface of the restricted cross-section.

9. The apparatus according to claim 6, wherein the adjacent sections of the upper surface of the restricted cross-section are arranged, in a vertical orientation and a horizontal orientation in relation to a lower surface of the restricted cross-section.

10. The apparatus according to claim 6, wherein the predefined gap is in a range of 10-20 mm arranged between the adjacent sections of the upper surface of the restricted cross-section.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) In the following an embodiment of the invention is discussed in greater detail in the sense of example and with reference to accompanying drawings, where

(2) FIG. 1 shows schematically an extruder-type slipform casting apparatus,

(3) FIG. 2A shows an embodiment of a trowelling plate assembly of an embodiment of the invention,

(4) FIG. 2B shows an alternative embodiment of a trowelling plate assembly of the invention,

(5) FIGS. 3A and 3B shows examples of concrete product shapes cast with a trowelling plate of an embodiment of the invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

(6) FIG. 1 shows schematically an extruder-type slipform casting apparatus 1, which is operated during slipform casting process by feeding concrete mass from a concrete mass container 2 to feed screws 3, which feed screws extrude the concrete mass under pressure in a slipform casting mold formed by a casting bed 5, side plates 6, and a top trowelling plate 7. After the top trowelling plate 7 is located a levelling plate 8. At the downstream end of the feed screws 3 is connected core forming members or mandrels 4, which also restricts the slipfom casting mold and form cores as longitudinal voids in the slab to be cast. The concrete mass is compacted during the slipform casting process by the rotating motion of the feed screws 3 extruding the concrete mass achieved with a drive motor 9, and by back-and-forth movement in the casting direction of the feed screws and the core forming members 4 achieved with a drive motor 10. The outer surfaces of the product to be cast are compacted by back-and-forth movement of the side plates 6, and trowelling motion of the top trowelling plate achieved with a drive motor 11.

(7) FIGS. 2A and 2B shows embodiments of trowelling beam assemblies 12, 12 of the invention, which form the top surface of the restricted cross-section of a slipform mold forming the product to be cast.

(8) In the embodiment of FIG. 2A the trowelling beam assembly 12 comprises a frame part 13, through which the trowelling beam assembly is connected to the frame of the extruder-type slipform casting machine, a motor 11 for moving the three trowelling plate sections 7a, 7b and 7c. The motor 11 rotates a crankshaft (within the assemblies in FIGS. 2A and 2b) extending horizontally in transversal direction in relation to the movement directions of the trowelling plate over the trowelling plate sections 7a, 7b and 7c. The trowelling plate sections 7a, 7b and 7c are connected to the crankshaft via connecting rods, which cause the plate sections to move in back-and-forth movement when the drive shaft rotates. The connecting rods are connected to the crankshaft so, that the adjacent sections of the trowelling plate move in different phases in relation to each other, preferably in opposite phases so that the adjacent sections move opposite direction during the whole movement distance. The trowelling plate sections 7a, 7b and 7c are also connected to the frame part 13 via swivel arms 14.

(9) After the trowelling plate sections 7a, 7b and 7c is located a levelling plate 8, which finishes and levels the upper surface of the concrete product to be cast.

(10) In the embodiment of FIG. 2A the trowelling plate comprises three sections 7a, 7b and 7c, which are vertically aligned, so that the upper surface compacted with this embodiment will be level. The distance between the sections 7a, 7b and 7c is about 0.5-2 mm when uniform upper surface for the product to be cast is to be achieved. If reinforcement parts or other objects extending from the upper surface of the product to be cast are required, the distance between the sections 7a, 7b and 7c is about 10-20 mm, which allows these parts to pass through the trowelling plate between the sections.

(11) The embodiment of FIG. 2B corresponds to the embodiment of FIG. 2A with the exception of the shape of the trowelling plate sections 7a, 7b and 7c, and the shape of the levelling plate 8.

(12) In the embodiment of FIG. 2B the sections 7a and 7c at the sides of the trowelling plate are formed so, that they comprise both vertically and horizontally extending trowelling surfaces, and the middle section 7b comprises only horizontally extending trowelling surface. The shape formed for the upper surface of the product to be cast can best be seen from the shape of the levelling plate 8, and an example of the shape of a concrete product cast with this trowelling plate is shown in FIG. 3B.

(13) FIGS. 3A and 3B shows examples of concrete product shapes cast with a trowelling plate of an embodiment of the invention. As mentioned in previous paragraph, the trowelling plate assembly of FIG. 2B is used in casting the concrete product shape of FIG. 3B.

(14) The casting of concrete product shape show in FIG. 3A requires trowelling plate formed of 5 to 9 sections. The side sections of the trowelling plate may be formed as substantially L-shaped trowelling both horizontal and vertical surfaces of the concrete product with a single section, and the middle portion may be formed with a substantially U-shaped trowelling plate section. Alternatively, each of the horizontal surfaces and vertical surfaces connecting the horizontal surfaces may be trowelled with a separate troweling plate sections.

(15) The specific exemplifying embodiments of the invention shown in figures and discussed above should not be construed as limiting. A person skilled in the art can amend and modify the embodiments in many evident ways within the scope of the attached claims. Thus the invention is not limited merely to the embodiments described above.