Plastic article or earthenware shaping or treating: apparatus – With apparatus assembly or dismantling means or with idle part – Plural wear or shaping surfaces mounted for alternative use
Reexamination Certificate
1998-12-14
2001-05-15
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With apparatus assembly or dismantling means or with idle part
Plural wear or shaping surfaces mounted for alternative use
C425S456000, C404S114000, C404S118000
Reexamination Certificate
active
06231331
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a vibratory screed device for levelling freshly poured concrete surfaces, comprising:
an elongated vibrated screed beam delimited by a flat underside, a first and a second longitudinal side and a top;
a vibratory assembly for bringing the vibrated screed beam into vibration; and
a handle assembly which is fixed, or can be fixed, in a detachable manner, to the vibrated screed beam at an upward slope with respect to the flat underside and essentially transversely to the vibrated screed beam.
BACKGROUND OF THE INVENTION
A vibratory screed device of this type is disclosed, for example, in US Patent U.S. Pat. No. 5,540,519. This publication discloses a vibratory screed device having an elongated vibrated screed beam which in cross-section is in the shape of an equilateral triangle. The vibrated screed beam is delimited by a flat underside, the first side of the triangle, by a first and second longitudinal side, the first and second sides of the triangle, and a top, specifically the apex or rib of the triangle. Furthermore, a handle assembly is provided which can be fitted, such that in principle it can be detached, on the vibrated screed beam, in particular on one of the longitudinal sides, such that it then slopes upwards with respect to the flat underside, transversely to the vibrated screed beam. A vibratory motor is fitted in the handle assembly, which motor transmits vibrations to the vibrated beam via a driven shaft and a vibratory rod fitted in the vibrated screed beam. Incidentally, it is pointed out that the installation based on the said patent which is available on the market has a different vibratory assembly without the vibratory rod fitted in the vibrated screed beam. In the case of the version obtainable on the market, the vibrations are transmitted to the outside of the vibrated screed beam from a vibration source fitted on the handle assembly.
As such, vibratory screed devices for levelling freshly poured concrete surfaces have already been known for several decades. In this context a very large number of vibrated screed beams of different constructions have already been designed for diverse specific applications. In general the requirements in respect of a vibrated screed beam for relatively wet concrete differ from those for relatively dry concrete. A further point is that vibratory screed devices of this type can be used in a manner in which they float on the concrete, but can also be used in a supported manner, in which case road forms, on which the ends of the vibrated screed beam bear, are placed at the side of the concrete surface or in the concrete surface. The intention with all of these vibratory screed devices is to level freshly poured concrete surfaces and, in doing so, also to compact the concrete by means of vibration. Depending on the specific application, a different vibratory screed device or at least a different vibrated screed beam must therefore always be used. This means that a number of different types of vibratory screed devices or at least a number of different types of vibrated screed beams must be kept in stock. There are manufacturers who respond to this by marketing various types of vibrated screed beams.
SUMMARY OF THE INVENTION
The aim of the present invention is, now, to provide a vibratory screed device of the type specified in the preamble which can be used for more than one specific application, and in particular to provide a relatively universal vibratory screed device.
The aim is achieved with a vibratory screed device of the type specified in the preamble in that the handle assembly and the vibrated screed beam are provided with coupling means which are capable of interacting with one another and which are constructed such that the handle assembly can be fixed to the vibrated screed beam, in such a way that it can be detached therefrom, in a first position or a second position, wherein in the first position the handle assembly slopes upwards obliquely at the first longitudinal side of the vibrated screed beam and wherein in the second position the handle assembly slopes upwards obliquely at the second longitudinal side and in that the first and the second longitudinal side are differently profiled and each has a surface suitable for vibratory levelling. This aim can be achieved by constructing the handle assembly such that it can be fixed on the vibrated screed beam in two different positions, in particular sloping upwards from the one longitudinal side and from the other longitudinal side, and such that it can also be detached again, and providing the vibrated screed beam with a differently profiled surface on its two opposing longitudinal sides. In this context a differently profiled surface can be understood, for example, as a first longitudinal side which is essentially perpendicular to the flat underside and a second longitudinal side which, for example, makes an acute angle of between 45° and 90°, or optionally smaller than 45°, with the flat underside. In this way it is possible for the user, for example depending on his own specific preference, to select the one or the other longitudinal side as the active side, that is to say the side facing the direction in which the vibratory screed device is pulled. Such a preference can even be personal, so that for otherwise identical conditions a different selection is made depending on the person.
According to the invention, however, it is particularly advantageous if the first and the second longitudinal side are provided with mutually different profiles such that they form surfaces which act in a manner which differs from one another. For instance, the one type of profiled surface is particularly suitable for obtaining a scraping-flat action, while the other type of surface is particularly suitable for a smoothing-flat action. In the case of a scraping action, consideration can be given, for example, to the more or less sharp cutting edge at the bottom front of the active longitudinal side frequently required for this purpose. In the case of a smoothing-flat action a sharp cutting edge of this type is frequently not desired since this can give rise to unnecessary plunging of the vibrated screed beam.
According to a further, particular embodiment of the invention, the first longitudinal side is in particular suitable for relatively wet concrete and the second longitudinal side is in particular suitable for relatively dry concrete. It will be clear that the first and the second longitudinal side can also be reversed here. Specifically, the important difference in levelling freshly poured concrete frequently lies in the wetness of the concrete. In the case of very wet concrete the smoothing-flat action is in general the most important and in the case of relatively drier to already substantially dry or possibly even already partially set concrete the scraping action is frequently much more important. With a vibratory screed device of this type it is also conceivable that the concrete is already levelled while relatively wet using the first longitudinal side and subsequently, when the concrete has already set sufficiently or set somewhat and thus has become drier, a further levelling operation, which can also be termed post-levelling is carried out using the second longitudinal side.
If the scraping action is important, it is particularly advantageous according to the invention if the second (or optionally first) longitudinal side has a surface of concave cross-section adjoining the underside. In this way a relatively sharp cutting edge is obtained at the bottom, with an adjoining surface which bends away in the direction opposite to the direction of pulling and then bends back into the direction of pulling, which in combination with the vibration of the vibrated screed beam causes the concrete scraped off to curl up and, in turn, fall back.
According to a further advantageous embodiment, the vibratory screed device according to the invention comprises a first longitudinal side with a surface which adjoins the underside and i
Bouwmachinefabriek Lievers B.V.
Davis Robert
Del Sole Joseph S.
Young & Thompson
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