Title:
CONCRETE-FINISHING APPARATUS
Kind Code:
A1


Abstract:
A concrete-finishing apparatus (10) comprises a relatively quickly rotating, powered roller (18) adapted to be moved relatively slowly across a bed, slab or layer of newly-laid concrete (11), while the latter is still fluid, with opposite ends (14, 15) of the roller maintained at the required level of the concrete surface, in order to produce a smoothed finish to the surface of the concrete, said roller (18): a) containing internal stressing means (44) for applying longitudinal compression to the roller, between the ends (14, 15) of the roller, so as to reduce the tendency of the roller to sag or become permanently bowed, and/or b) being adapted to be removed from the remainder of the apparatus (10) and dismantled, when not in use, into constituent, smaller, parts.



Inventors:
Williamson, John (CHESTERFIELD, GB)
Application Number:
09/011676
Publication Date:
02/28/2002
Filing Date:
02/14/1998
Assignee:
WILLIAMSON JOHN
Primary Class:
Other Classes:
404/122
International Classes:
E01C19/29; E04G21/10; (IPC1-7): E01C19/22
View Patent Images:
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Primary Examiner:
ADDIE, RAYMOND W
Attorney, Agent or Firm:
NORTON ROSE FULBRIGHT US LLP (NEW YORK, NY, US)
Claims:
1. A fluid finishing apparatus such as a concrete finishing apparatus or the like, comprising a rotatable, powered roller adapted to be moved over a surface of newly laid fluid which is adapted to set, cure or otherwise solidify, with the roller surface in slipping contact with the fluid surface and with opposite ends of the roller maintained at the required level of the fluid surface, in order to produce a smooth finish to the surface of the fluid, said roller comprising means to maintain the roller at the required level of the concrete surface along the entire length thereof, thereby to reduce the tendency of the roller to sag or become permanently bowed, characterised in that the means comprise internal stressing means for applying longitudinal compression to the roller, between the ends of the roller.

2. A concrete-finishing apparatus according to claim 1, comprising a relatively quickly rotating, powered roller adapted to be moved relatively slowly across a bed, slab or layer of newly-laid concrete, while the latter is still fluid, with opposite ends of the roller maintained at the required level of the concrete surface, in order to produce a smoothed finish to the surface of the concrete, said roller being adapted to be removed from the remainder of the apparatus and dismantled, when not in use, into constituent, smaller parts.

3. A concrete-finishing apparatus as claimed in claims 1 or 2, wherein the internal stressing means preferably comprises one or more longitudinal tensioning members each extending between and interconnecting two end-plates, one at either end of the roller.

4. A concrete-finishing apparatus as claimed in claim 3, wherein the or each tensioning member comprises a cable, or a rigid rod, or a combination thereof.

5. A concrete-finishing apparatus as claimed in claim 4, wherein the rod is wholly or partly screw-threaded for tightening the tensioning member so as to prestress the roller.

6. A concrete-finishing apparatus as claimed in any one of claims 3 to 5, wherein the tensioning member may be removed from the roller and both member and roller may be dismantled into respectively constituent smaller lengths and parts and may be reassembled with use of only some of their constituent lengths and parts, or with use of all of said lengths and parts together with additional lengths and parts, whereby the length of the member and of the roller may be adapted in convenient manner.

7. A concrete-finishing apparatus as claimed in any one of claims 2 to 6, wherein the aforesaid smaller parts comprise rigid cylindrical roller sections, with the axial ends of their cylindrical surfaces tightly held together in axial end-to-end abutment.

8. A concrete-finishing apparatus as claimed in claim 7, wherein the surfaces themselves form the surface of the roller, or wherein one or more sleeves are fitted over the roller sections.

9. A concrete finishing apparatus as claimed in any of claims 2 to 8 wherein one or more of the smaller parts may comprise dedicated end plates and/or dedicated coupling members, i.e. providing essentially end and/or coupling portions, and substantially no roller surface portion.

10. A concrete finishing apparatus as claimed in any of claims 2 to 9 wherein the smaller parts may be of any number and individual length as required to enable the construction of a roller of desired length and to maintain the integrity thereof.

11. A concrete finishing apparatus as claimed in any of claims 2 to 10 wherein the smaller parts comprise an integral or a removable coupling portion at each end thereof, which coupling portions are male and female respectively, the male coupling portion providing an end handle, thereby enabling the assembly of a complete roller with use of any one or more roller sections and a single dedicated end plate.

12. A concrete finishing apparatus as claimed in any one of claims 2 to 11, wherein the roller comprises a kit of parts comprising a plurality of roller sections of different lengths and one or more dedicated end plates, in addition comprising an internal tensioning member or its constituent parts, in particular in addition comprising a plurality of dedicated coupling members.

13. A process for fluid, such as concrete, surface finishing comprising drawing the apparatus of claims 1-11 across the fluid in the opposite direction to that in which the rotation of the roller is tending to move the apparatus.

14. A process according to claim 13 wherein the roller is supported at its ends and the central deflection is measured, enabling deflection to be reduced to an acceptable level by adjustment of internal stressing means.

15. A process of assembly or dismantling an apparatus according to any of claims 1-12.

Description:

FIELD OF THE INVENTION

[0001] This invention relates to a concrete-finishing apparatus, that is, apparatus comprising a relatively quickly rotating roller adapted to be moved relatively slowly across a bed, slab or layer or newly-laid concrete, while the latter is still fluid, in order to produce a smoothed surface thereon.

[0002] Prior Art

[0003] It is well established, indeed, it is conventional practice, after concrete has been laid to form a slab within confining “formwork”, and while the concrete is still fluid, for “striking-off”, or surface finishing, of the concrete, to be carried out.

[0004] Conventionally, striking-off has been achieved by means of a wooden or metal beam, known as a “screed” or “strike-off template”, being pulled over the surface of the concrete, with the ends of the beam resting upon wooden or metal screed boards, the latter effectively forming part of the concrete-confining formwork, at opposite edges of the concrete.

[0005] It is now well established, however, instead of a beam, to use a rotary roll tube, that is, a tubular roller, powered (i.e. rotated) by an air motor, hydraulic motor, electric motor or internal combustion engine, for the quick striking-off (i.e. surface-finishing) of newly laid, still fluid, or still unset, concrete. The ends of the roller overhang, and rest upon, the formwork so that the roller is maintained at the required level for the surface of the concrete. [Before concrete properly “sets”, it becomes thixotropic, in which state it assumes a stable, quasi-set condition, but can be fluidized by pokering, that is, mechanical working.]

[0006] Whichever implement is used, that is, a beam or roller, it has to traverse the full width of the concrete, and overhang the formwork, but should not overhang the formwork excessively. That is to say, the length of the beam or roller has to be matched to the width of the concrete. Hence it has been necessary to stock a large range of lengths of beams and rollers.

[0007] Long rollers are inconvenient to handle and to transport, and are liable to damage easily. Known tubular rollers tend to sag during use, producing an unwanted concave surface on the concrete. Known tubular rollers also are liable to becoming permanently bowed in storage or in transport, with the result that the concrete surface becomes wavy or at any rate uneven with the rotation of the roller.

[0008] Examples of relevant prior art include two United States Patent Specifications, U.S. Pat. Nos. 4,142,815 (Mitchell) and 4,702,640 (Allen)—U.S. Pat. No. 4,142,815 (MITCHELL) and U.S. Pat. No. 4,702,640 (ALLEN). Reference is directed to both specifications. Slightly less relevant is a third United States Patent Specification, U.S. Pat. No. 4,993,869 (Ulmer et al)—U.S. Pat. No. 4,993,869 (ULMER ET AL).

[0009] U.S. Pat. No. 4,142,815 (MITCHELL) discloses a concrete slab striker which employs a counter-rotating roller to grade, or strike off, the concrete of a freshly poured concrete slab while the concrete is still in the plastic state. Preferably the roller is formed from steel tubing, which may be filled with concrete for additional weight.

[0010] U.S. Pat. No. 4,702,640 (ALLEN) discloses a concrete finisher controlled and driven by an end handle assembly including an internal combustion engine for rotating a tubular roller.

[0011] U.S. Pat. No. 4,993,869 (ULMER ET AL) discloses a concrete finishing machine with vibrating finishing rollers.

[0012] None of these three specifications however addresses two problems with which the present invention is concerned. One such problem is the above-mentioned tendency of a concrete-finishing roller to sag, or become (permanently) bowed, due to its own weight, whereby the concrete is finished with an unintentionally non-flat surface. The other problem is that the roller(s) cannot be taken apart, or dissembled, either prior to use or subsequent to use.

SUMMARY OF THE INVENTION

[0013] In its broadest aspect the invention relates to a fluid finishing apparatus such as a concrete finishing apparatus or the like, comprising a rotable, powered roller adapted to be moved over a surface of newly laid fluid which is adapted to set, cure or otherwise solidify, with the roller surface in slipping contact with the fluid surface and with opposite ends of the roller maintained at the required level of the fluid surface, in order to produce a smooth finish to the surface of the fluid, said roller comprising means to maintain the roller at the required level of the concrete surface along the entire length thereof, thereby to reduce the tendency of the roller to sag or become permanently bowed.

[0014] There are a number of different aspects to the invention.

[0015] According to a first aspect of the invention there is provided a concrete-finishing apparatus comprising a relatively quickly rotating, powered roller adapted to be moved relatively slowly across a bed, slab or layer or newly-laid concrete, while the latter is still fluid, with opposite ends of the roller maintained at the required level of the concrete surface, in order to produce a smoothed finish to the surface of the concrete, said roller containing internal stressing means for applying longitudinal compression to the roller, between the ends of the roller, so as to reduce the tendency of the roller to sag or become permanently bowed. Suitably internal stressing serves to maintain the roller at the required level of the concrete surface, along the entire length of the roller.

[0016] According to a second aspect of the invention there is provided a concrete-finishing apparatus comprising a relatively quickly rotating, powered roller adapted to be moved relatively slowly across a bed, slab or layer or newly-laid concrete, while the latter is still fluid, with the opposite ends of the roller maintained at the required level of the concrete surface, in order to produce a smoothed finish to the surface of the concrete, said roller being adapted to be removed from the remainder of the apparatus and dismantled, when not in use, into constituent, smaller, parts.

[0017] Said constituent smaller parts may or may not remain loosely inter-connected after the dismantling.

[0018] According to a third aspect of the invention there is provided a concrete-finishing apparatus comprising a relatively quickly rotating, powered roller adapted to be moved relatively slowly across a bed, slab or layer of newly-laid concrete, while the latter is still fluid, with opposite ends of the roller maintained at the required level of the concrete surface, in order to produce a smoothed finish to the surface of the concrete, said roller:

[0019] a) containing internal stressing means for longitudinal compression to the roller, between the ends of the roller, so as to reduce the tendency of the roller to sag or become permanently bowed; and

[0020] b) being adapted to be removed from the remainder of the apparatus and dismantled, when not in use, into constituent, smaller, parts.

[0021] Suitably internal stressing serves to maintain the roller at the required level of the concrete surface, along the entire length of the roller.

[0022] Said constituent smaller parts may or may not remain loosely inter-connected after the dismantling.

[0023] The apparatus of the invention may serve as a fluid-finishing apparatus for any material which when newly laid is fluid and thereafter sets, cures or solidifies to form a desired product, in particular materials for construction of buildings, roads, foundations or like structures in particular concrete, but also cement, tars or bitumens and the like.

[0024] The roller of a concrete-finishing apparatus in accordance with the first, second or third aspect of the invention is preferably adapted to be driven, that is, rotated, by an engine or motor, either directly or through a gearbox, at between 50 and 500, preferably between 100 and 300, revolutions per minute (“rpm”) and the apparatus is preferably adapted to be drawn over the concrete by means of two handles at opposite ends of the roller, and/or by means of a winch, or possibly two winches, positioned at one end of the concrete. Reference herein to “relatively quickly rotating powered roller adapted to be moved relatively slowly” is to the respective speeds of rotation, whereby the roller is caused to move and also causes the concrete surface to be displaced, i.e. a shear force is applied to the surface. It may be possible to operate the apparatus optionally or alternatively in other manner with respect to the relative speed of rotation and movement of the roller or the like in order to achieve a desired surface finishing. In use, the apparatus is preferably drawn across the concrete in the opposite direction to that in which the rotation of the roller is tending to move the apparatus, i.e. such that the coincident surfaces of the roller and concrete serve to displace excess concrete towards that part of the concrete surface which has not yet been smoothed. Advantageously this provides a superior finish. Preferably the powered roller is relatively quickly rotating in use, and is moved relatively slowly across the surface of the concrete.

[0025] In the case of the preferred embodiments of the first and third aspects of the invention, that is, in the case where the roller contains internal stressing means for applying longitudinal compression to the roller, between the ends of the roller, so as to reduce the tendency of the roller to sag or become permanently bowed, the internal stressing means preferably comprises one or more longitudinal tensioning members (preferably more than one) extending between and interconnecting two end-plates, one at either end of the roller. The or each tensioning member may comprise a cable, or a rigid rod, or a combination thereof. The rod may be wholly or partly screw-threaded for tightening the tensioning member so as to prestress the roller. A preferred form of tensioning member comprises a cable joined securely at opposite ends respectively to two screw-threaded rods, each said rod being connected to a respective one of the two end-plates. Preferably a single such tensioning member is provided within the roller, extending axially therein. Preferably, a plurality, for example three or four of such tensioning members are provided within the roller, equidistantly from each other and equidistantly from the axis of the roller. The cable may be joined to each rod by a sleeve which is swaged onto the cable and is screwed onto the rod. In the case of the preferred embodiment of the third aspect of the invention, the longitudinal tensioning member may be removed from the roller and dismantled into constituent smaller lengths, and may be reassembled with use of only some of its constituent lengths, or with use of all of said lengths together with additional lengths, whereby the length of the member may be adapted in convenient manner. Preferably the tensioning member comprises one or more rod sections at one or both ends and a single cable section therebetween or comprises a single rod or cable section, each rod or cable section preferably constituting a constituent length.

[0026] In the case of the preferred embodiments of the second and third aspects of the invention, that is, in the case where the roller can be removed from the remainder of the apparatus and dismantled, when not in use, into constituent, smaller parts, the roller may be dismantled for the purpose of reassembling with use of only some of its constituent parts, or with use of all of said parts together with additional parts, whereby the length of the roller may be adapted in convenient manner. The aforesaid smaller parts may comprise rigid cylindrical roller sections, with the axial ends of their cylindrical surfaces tightly held together in axial end-to-end abutment. Additionally one or more of the aforesaid smaller parts may comprise dedicated end plates and/or dedicated coupling members, i.e. providing essentially end and/or coupling portions, and substantially no roller surface portion.

[0027] The aforesaid member smaller parts may be of any number and individual length as required to enable the construction of a roller of desired length, and to maintain the integrity thereof, preferably are of 2 or more in number, for example 2 to 15, more preferably 2 to 10. The smaller parts are suitably of length enabling convenient transport and assembly acceptable lengthwise rigidity (i.e. so as not to sag or become permanently bowed), preferably are of length of 1 to 5 multiples of 0.3 to 1.8 m, more preferably 1 to 5 multiples of 0.5 to 1.5 m for example 1 to 5 multiples of the order of 1.0 m.

[0028] Preferably roller sections comprise an integral or removable coupling portion at each end thereof, thereby enabling the coupling of roller sections end-to-end. Such coupling portions may be like and adapted to couple with a dedicated coupling member, or may be effectively male and female respectively and adapted to couple directly with one coupling portion of another roller section. Preferably one coupling portion of each roller section provides also an integral or removable end plate, for example the male coupling portion provides an end handle, and an attachment means for the tensioning member, and a dedicated end plate provides also a male coupling portion thereby enabling the assembly of a complete roller with use of any one or more roller sections and a single dedicated end plate.

[0029] Preferably integral coupling portions/end plates comprise one or more apertures therein to receive the tensioning member(s) along the length of the roller. Preferably a single tensioning member passes through an aperture in the recess or projection of each female or male coupling portion.

[0030] Either the surfaces themselves of the roller sections may form the surface of the roller, or one or more sleeves may be fitted over the roller sections.

[0031] For example, a single sleeve may be fitted over all the roller sections. Alternatively a plurality of, i.e. several, sleeves may be fitted over the roller sections. Sleeve ends may coincide with roller section ends or, preferably, sleeve ends may be staggered axially in relation to the roller ends, so that the sleeve ends are out of registry with the roller section ends. Such sleeves may be formed from sheets, curved into cylindrical forms, the ends of the sheets being tucked into surface slots, parallel to the roller axis, in the roller sections. Such sleeves may be sacrificial, that is, designed to wear away in use and to be replaceable.

[0032] According to a fourth aspect of the invention there is therefore provided a kit of parts for a roller as hereinbefore defined, comprising a plurality of roller sections of different lengths and one or more dedicated end plates. Preferably the kit comprises in addition a tensioning member or its constituent parts, for example one (or more) cable section(s of different lengths) and a plurality of (pairs of) rod sections of different lengths, rod sections of any pair being of similar length. Optionally the kit comprises a plurality of dedicated coupling members.

[0033] In a specific embodiment therefore the invention relates to an apparatus for use in striking-off or finishing newly laid, still fluid, concrete on site; said apparatus comprising a roller having a cylindrical or nearly cylindrical outer surface which extends the whole length, or substantially the whole length, of the roller, for striking-off concrete; i.e. said apparatus being a powered striker roller; each end of the roller being rotatably connected to a respective guidably moveable support of said powered striker roller; one or both end(s) of the roller being formed as, or provided with, a (respective) shaft drivably coupling the roller to a motor or engine of said powered striker roller, for rotating the roller in use at a speed in the range of 50 revolutions per minute (“rpm”) to 500 rpm; each end of the roller being directly or indirectly connected to a handle or the like, and/or to a winch or the like, for moving the roller over the concrete with the cylindrical or nearly cylindrical outer surface of the roller in slipping contact with the surface of the concrete; the roller being characterised in that the roller is an assembly of constituent parts, at least some of which are rigid and impart rigidity to the roller; in that at least some of the constituent parts of the roller are in the form of cylindrical or nearly cylindrical or part-cylindrical or part-nearly cylindrical members abutting closely together so as to leave no gaps or only very small gaps between them so as to form or define said cylindrical or nearly cylindrical outer surface of the roller; and in that the roller can be partly or completely dissembled, before and/or after use, into its constituent parts, for ease of transport to and/or away from the site, and/or for replacement of a damaged part, and/or for varying the effective span of the roller.

[0034] The rigid constituent parts of the apparatus may comprise a plurality of cylindrical or nearly cylindrical roller sections axially abutted together to form or define the cylindrical or nearly cylindrical outer surface of the roller. Each roller section is preferably tubular.

[0035] Preferably tensioning means extends throughout the interior or the roller from one end to the other end of the roller, for applying tension between the ends of the roller and thereby reducing a tendency of the roller otherwise to sag, the tensioning means being adapted so that the tension can be completely removed before or after use for the roller sections to be disconnected from each other.

[0036] The roller sections may be two or three or more in number, being formed by two end sections or by two end sections and one or more intermediate sections of the roller, each said ends section being formed with, or provided with, respective bearings, comprising the two bearings whereby the roller is supported or is adapted to be supported rotatably by the machine.

[0037] The roller sections may inter-engage via unthreaded co-axial taper portions, one male, one female, inter-engaging with each other.

[0038] One or more relatively thin cylindrical or nearly cylindrical sleeves may form said cylindrical or nearly cylindrical outer surface, and may be sacrificial and replaceable.

[0039] The constituent parts, or some of them, may be still loosely joined together or may be completely separated from each other after the dissembly of the roller.

[0040] The invention will be further described, by way of example only, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 illustrates one form of apparatus embodying the invention in use on a bed of fluid concrete;

[0042] FIG. 1A is an enlargement of a detail in FIG. 1;

[0043] FIG. 2 illustrates another form of apparatus embodying the invention in use on a bed of fluid concrete;

[0044] FIG. 3 illustrates yet another form of apparatus embodying the invention in use on a bed of fluid concrete;

[0045] FIGS. 3A, 3B, 3C and 3D are enlargements of details of FIG. 3;

[0046] FIG. 4 is a schematic side elevation of a three-section roller of one apparatus embodying the invention;

[0047] FIG. 5 is a schematic side elevation of a longitudinal tensioning member of stressing means shown in the embodiment of FIG. 1;

[0048] FIG. 6 is an enlarged end view of the stressing means;

[0049] FIG. 7 is a part-sectional view taken on line B-B in FIG. 6;

[0050] FIG. 8 is an enlarged view of an end-plate of the stressing means;

[0051] FIGS. 9-11 illustrate a sleeve on two roller sections;

[0052] FIGS. 12-14 illustrate oblique abutment surfaces;

[0053] FIGS. 15-17 illustrate castellated abutment surfaces;

[0054] FIGS. 18-22 show tapered male and female end portions provided on the respective roller sections;

[0055] FIGS. 23-25 and FIGS. 26-28 respectively illustrate internal and external tubular bridging members;

[0056] FIGS. 29-34 show a roller covered by a removable sleeve;

[0057] FIGS. 35-37 illustrate two rods coupled together;

[0058] FIGS. 38-40 show part of a solid roller;

[0059] FIGS. 41-45 show male and female end-plates with mating conical locating formations;

[0060] FIGS. 46-48 and FIGS. 49-54 show two variations on this;

[0061] FIGS. 55-56 show a one-piece stressed roller;

[0062] FIG. 57 shows a coupling;

[0063] FIGS. 58 and 59 show two forms of multi-section roller;

[0064] FIG. 60 shows another form of tensioning member;

[0065] FIG. 61 shows an unstressed, three-section, roller;

DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS

[0066] Referring to the drawings, the apparatus 10 of FIG. 1 is adapted to be drawn across a bed of still fluid concrete 11 by means of two handles 12, 13 with the roller ends 14, 15 resting upon formwork 16, 17 which the ends overhang. The roller 18 is powered by means of a mains-powered electric motor 19.

[0067] The apparatus 20 of FIG. 2 is similar except for two winches 21, 22 for drawing the apparatus over the concrete.

[0068] FIG. 3 illustrates a more robust apparatus 30 wherein the roller 31 is rotatably mounted to two carriages 32, 33, one having a roller-powering motor 34. The formwork comprises two U-section beams 35, 36 on their sides. The roller ends rest upon the tops of the beams 35, 36 whilst the carriages 32, 33 have relatively small guide-rollers 37, 38 which engage undersides or two top flanges of the beams 35, 36, so as to hold the roller 31 positively down, in contact with the formwork beams 35, 36, this does away with the need for handles. The apparatus 30 is drawn over the concrete by two winches 39, 40.

[0069] Referring now to FIG. 4, the strike-off roller or roll tube 41 illustrated in FIG. 1 is, for example, 4 to 5 m long and 120 mm in diameter. It is in the form of an elongate hollow cylindrical body and consists of two identical end sections 42, 42 and a middle section 43 (which can be replaced by a shorter or longer middle section, not shown). The sections 42, 43, 42 are separably connected end-to-end as shown.

[0070] The roller 41 comprises stressing means 44 comprising 4 four tensioning members 45, only one of which is shown, extending between two end plates 46, 46. The tensioning members 45 are equally spaced from one another around the axis of the roller and are equally spaced from the axis. The number of longitudinal tensioning members may be selected depending on the size of the roller. It is possible to use a single longitudinal tensioning member. However, there are preferably at least three. Each tensioning member 45 has two end nuts 47 engaging the end plates 46, 46 and tightened so as to put the tensioning member 45 in tension, whereby the roller 41 is put under end-to-end compression and thereby resists sagging and/or becoming bowed. Each member 45 comprises two rods 48, 48 connected by a cable 49 whose length is selected depending on the length of the middle section 43; the cable 49 may be replaced by a chain, rope, strand or wire, for example. Each end of the cable 49 is releasably connected to the associated rod 48 by a coupling 50, which may comprise a sleeve swaged on the cable and screwed onto the rod. The free end of each rod 48 has a screwthread engaged with nut 47 which bears against the end plate 46 via an optional washer.

[0071] Tightening of the nuts 47 puts the longitudinal tensioning members 45 under tension and consequently puts the roller 41 under longitudinal compression. This not only ensures that the sections 42, 43, 42 are securely joined together but also stiffens the roller 41 in order to resist bending. When a horizontal cylindrical body bends under its own weight, the uppermost generatrix shortens and the lowermost generatrix lengthens (elastic deformation). The stressing means 45 applies compression to all of the generatrices thereby resisting extension of the lowermost generatrix and consequently resisting bending of the body. For a roller 4 m long and 120 mm in diameter, the central deflection as measured by rolling the roller with its ends resting on parallel screed boards may be improved from 30 mm using a conventional roll tube to a range round the circumference of 0 to 3 mm using a roller as described above. Thus, it is possible to minimize the deflection on a particular span or to achieve a longer span with a still acceptable deflection. It is also possible to increase the diameter of the roller, using an increased number of longitudinal tensioning members 45.

[0072] A roller of a desired length may be made up from a kit of parts including end sections 42 and middle sections 43 of various lengths, from which the sections to be joined end-to-end are selected. Rods 48 and cables 49 of suitable length are then selected accordingly, and the roll tube as shown in FIG. 4 is assembled. The roller is then supported at its ends, and the central deflection (sagging) is measured. In order to reduce this deflection to an acceptable level, the nuts 47 are tightened, preferably using a torque wrench to ensure that the tension in the members 45 is approximately equal.

[0073] It is to be noted that the roller 41 may have a diameter which decreases slightly and gradually from the end regions toward a central region, to provide a negative camber. This is useful, for example, if a surface which rises towards the middle of the floor is to be formed when the roller is rolled over the concrete.

[0074] The strike-off roller may be driven in rotation by drive means (including a motor) at one end of the roller, or at each end of the roller if the span is particularly large.

[0075] The sections of the roller 41 may be made of metal (e.g. steel or aluminium), plastics material, or even wood, for example. Materials of low density and high stiffness are preferred.

[0076] The elongate body may have, over at least the major part of its length, a circumferential wearing surface which is replaceable. The wearing surface may be constituted by a sleeve, which may be sectional and/or flexible. A flexible sleeve, e.g. of plastics sheet or textile fabric, may be fitted on site, may be rolled up for easy transportation, and may extend over the full length of the roller.

[0077] For example, FIGS. 9-11 illustrate such a sleeve 51 on roller sections 52, 52.

[0078] Various modifications may be made within the scope of the invention. For example, FIGS. 12-14 show an embodiment in which the abutment surface 53a, 53b on each section of the roller is a planar surface oblique to the axis of the roller, e.g. at an angle of 30 to 60°, preferably 45°. In FIGS. 15-17, the abutment surface again deviates from a plane normal to the axis of the roller and constituted by castellations 54a, 54b on the ends of the sections of the body. Both of these embodiments provide a staggered joint which avoids forming a noticeable line on the surface of the concrete.

[0079] The embodiment shown in FIGS. 18-22 has tapered male and female end portions 55a, 55b provided on the respective roller sections.

[0080] In the embodiment shown in FIGS. 23-25 the two abutting ends of the sections 56, 57 are bridged by an internal stiffening member 58 in the form of a tube, e.g. of rigid plastics material, of greater wall thickness than the tubular sections 56, 57.

[0081] In the embodiment of FIGS. 26-28, a relatively thin external tubular bridging member 59 fits within reduced diameter end sections 60, 61.

[0082] FIGS. 29-34 show a roller 62 covered by a removable sleeve 63 serving as the wearing surface mentioned above and extending along the whole length of the body. The ends 63a, 63b of sleeve 63 are fitted into an undercut slot 64 in roller 62, parallel to the roller axis.

[0083] Two rods 65a, 65b may be coupled end-to-end by the coupling 66 shown in FIGS. 35-37. Each rod 65a, 65b is cut away over more than half its cross-section at the end and a transverse plate 67a, 67b is welded to it. Each plate 67 is provided with a pair of holes 68a, 68b offset from the rod. The plates 67 are connected together by bolts 69 passed through the holes 68, with the interposition of a washer, and retained by a nut 70.

[0084] FIGS. 38-40 show part of a solid roller body 71 whose sections 72, 73 are joined by a threaded stub 74 on one section screwed into a threaded socket 75 in the other section. An optional removable sleeve 76, as described above, is also shown.

[0085] FIGS. 41-45 show male and female end-plates 77, 78 with mating conical locating formations 79, 80. FIGS. 46-48 show a variation on this.

[0086] FIGS. 49-54 show another variation, in which a double male conical fitting 91 engages two female conical end-plates 92, 92 fitted respectively to two roller sections.

[0087] FIGS. 55-56 show a one-piece stressed roller 93, containing stressing means as described and illustrated above.

[0088] FIG. 57 shows a coupling 94, the construction of which is clear from the drawing.

[0089] FIGS. 58 and 59 show two forms of multi-section rollers 95, 96. The roller sections in FIG. 58 have flat ends, whilst the roller sections in FIG. 59 have mating, non-flat ends.

[0090] FIG. 60 shows another form of tensioning member 97, the construction of which is as shown.

[0091] FIG. 61 shows an unstressed, four-section, roller 98, the sections 98a-98d being coupled together by male and female coupling members 99, 100.

[0092] FIG. 62 shows a roller section (101) having integral end plate (102) comprising an open ended cylindrical end handle (103) and a tensioning member mounting (104), and having coupling portion (105) comprising an opening (106) adapted to receive a similar cylindrical handle (103) of another roller section (101). The opening (106) and handle (103) may be engaged by means of mating studs and apertures in the respective supporting faces (102, 105) about opening (106) and handle (103), and secured by means of the tensioning to be applied, or may be engaged and secured by means of suitable threading on opening (106) and handle (103) or the supporting faces (102, 105).

[0093] A dedicated end portion is shown (107) having two end plates (103), one of which may associate with the coupling portion (106), thereby providing a complete roller.

[0094] A tensioning member (108) is provided along the axial length of the roller, via the open axis (109) thereof, suitably secured in place by means of tensioning plates (110) and thereafter tensioned, or about the axial length, via apertures (111) in similar manner.

[0095] FIG. 63 shows a kit of parts according to the fourth aspect of the invention as hereinbefore defined, comprising roller sections (112) of different lengths, suitably 2×, 3× and 4× unit lengths, where the unit length is dependent on the intended nature of the surface to be finished, suitably for concrete finishing, the unit length is 0.5-1.5 m, preferably 1 m or thereabouts. The sections (112) are shown each with an end plate (113) and a coupling member (114) (detail not shown). The kit also includes a dedicated end portion (115), and optional dedicated coupling members (116).

[0096] A tensioning member (117) is shown in its component parts, comprising cable (118) of 2× unit length and pairs of rods (119) each of 0.5×, 1×, 1,5×, 2×, 2.5× and 3.5× unit length, or 14 rods (120) each of 0.5× unit length, or 7 rods (120) each of 1× unit length.

[0097] It will be apparent that a kit may comprise any component part as hereinbefore defined with respect to the description and figures, or combination thereof.