Road structure – process – or apparatus – Apparatus – Screed or drag
Reexamination Certificate
2002-05-30
2004-02-24
Pezzuto, Robert E. (Department: 3671)
Road structure, process, or apparatus
Apparatus
Screed or drag
C404S097000
Reexamination Certificate
active
06695531
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to the field of slumping or flowing of a cementatious material, i.e. concrete, more particularly to a single operator, hand held vibratory tool for tamping and smoothing such material on a flat walkway or even a contoured curb.
BACKGROUND OF THE INVENTION
The present invention relates to a hand held, single person operated slumping implement for tamping and smoothing a concrete form, such as a walkway or curb, where the implement, also termed a screed, mounts a rotating eccentric to effect a vibratory action when desired.
Typically, for constructing a flat walkway or curb, forms, such as 2×4, or 2×6 wooden boards, are positioned about the periphery for the walkway or curb. Thereafter, preferably on top of a prepared base of stone, for example, a quantity of concrete is deposited. That is, it is known to deposit cementitious materials, i.e. concrete, on a base, by supplying the material to a hopper or the like from which the material is dispensed and to strike off the surface of the material with a profile forming device which may be attached to the hopper or may be separate from it.
One known form of profile forming device comprises a plate which may be vibrated and which strikes off excess material to produce the required surface configuration. It is known to use a rotatable device which is arranged to roll over the material so as to displace excess material ahead of itself and to leave the required surface configuration behind it.
Surface forming devices of known types are disadvantageous in that their manner of operation tends to result in the material slumping or flowing from higher to lower regions after the device has passed with the result that the surface configuration is different from the desired shape.
Numerous screeds, tools used to smooth and level freshly poured concrete, employ vibratory action to tamp and smooth the concrete in the final finishing step. U.S. Pat. No. 4,340,351, describes a vibratory concrete screed requiring two operators which is used in the final finishing of concrete. U.S. Pat. No. 4,641,995, describes a vibratory concrete screed which rides on forms to screed narrow strips of concrete, such as walks. The screed thereof is mounted on the operator via a complicated harness counter-weighted frame and is powered by electricity thus requiring the manipulation of lengthy extension cords and having electrical power on site.
Further, there are various types of expensive, highly sophisticated and complex equipment have been available for simultaneously finishing a concrete surface and forming curbs on the sides of an area of concrete. In addition, various types of comparatively inexpensive concrete finishing equipment in the form of triangular truss screeds have been available in the past as well as numerous attachments and accessories for these devices. By way of example, U.S. Pat. No. 4,316,715, discloses a vibratory concrete screed having spaced apart front and rear screed blades in combination with numerous different types of accessories and attachments for finishing a concrete surface. The latter patent specifically discloses a vertically and laterally adjustable blade extension bracket for forming a step on the side surface of an area of concrete.
There is additional prior art on devices or systems for slumping or forming concrete as reflected in the following U.S. Patents:
a.) U.S. No. 5,997,270, to LaBonte, relates to a flexible automated trowel for a sliding formwork machine to allow finishing of a continuous trapezoidal wall of the type having one rectangular side and one side inclined towards the top or with two angular sides. A mold supporting the trowel comprises two straight sides, an enlarging setback originating from a formwork line. A driveway cutter proceeds from the enlarging setback in the direction of the slope of the angular wall. The cutter may have a concave face which is to be placed against a moldable face to produce a superior convex face to the continuous wall. Materials like concrete for curbs, gutters, driveway entrances may be continuously poured and necessitate little or no finishing touches.
b.) U.S. Pat. No. 5,540,519, to Weber, teaches an extremely light-weight, portable floating power vibratory concrete “Wet Screed”, which is hand operated by a single finisher in order to strike off, tamp and smooth freshly poured concrete using only perimeter slab forms or curbs. The unique angular design of the enclosed hollow screed blade allows the operator to lower the handle and effectively use the rear 60 degree angled surface of the screed blade to cut down the height of the concrete to the desired grade, or raise the handle to effectively use the front 60 degree angled surface of the screed blade to float and maintain the desired grade. The flat aluminum bottom extending from the front angled surface to the rear angled surface of the screed blade functions to produce a smooth, near final finish while the vibratory action tamps the rock down and works the moisture to the concrete surface, thereby substantially increasing the finishing time while making the finisher's job much easier.
c.) U.S. No. 4,544,346, to Allen, discloses apparatus that simultaneously finishes the surface of an area of concrete and forms a curb along one or both sides of the area as the apparatus is translated along the length of the area. The apparatus includes a vibratory concrete finishing machine, such as a triangular truss concrete screed, having first and second sides and spaced apart front and rear screed blades. The two sides of the finishing machine are supported by roller support units which engage each of the spaced apart forms. Coupling means connects the first roller support unit to the first side of the finishing machine, adjusts the lateral spacing between the first side of the finishing machine and the form, and adjusts the elevation of the screed blades with respect to the form. A curb form is coupled to the finishing machine between the form and the first side of the finishing machine.
d.) U.S. Pat. No. 4,391,549, to Murray, is directed to continuously extruding curb forming machines for roads that may be equipped with a downwardly moving sharpened blade for use in the insertion of an expansion joint piece at appropriate intervals into the curb without stopping the operation of the machine while the expansion joint piece is inserted. The expansion joint piece may be well known felt material for this purpose and the inserting blade has a template attached thereto the surface of which conforms to the surface of the curb and thus to the surface of the expansion joint piece. As the blade moves into the partially cured concrete, the template forces the joint piece into the same concrete.
e.) U.S. Pat. No. 4,097,173, to Tout, relates to a machine having a frame, supported by wheels, where the frame supports three spaced-apart self-placing form units, which operate in conjunction with finishing rollers. The self-placing form units of the machine are faced with endless synthetic rubber belts, which are backed up by hinged steel pads, and the top and bottom of the self-placing form units are sealed with a plate having a lip at the edge, to overlap the synthetic rubber, so as to repel any foreign matter, or concrete mix, from entering the inside of the units. The machine is reversible in direction when desired, and is used for concrete curb and gutter construction.
f.) U. S. Pat. No. 4,028,036, to Farfor, teaches a system for molding the surface of a moldable material, such as wet cement, to be shaped to a desired configuration by a profile forming device moved longitudinally relative to the material and rotated about an axis transverse to the direction of bodily movement. The profile forming device is eccentrically mounted or otherwise shaped to produce cyclic variation in level in the longitudinal direction and has a variable configuration along its length to provide a transverse variation in level of the surface. The profile forming device is driven at a speed to cause rubb
Noll William B.
Pechhold Alexander K.
Pezzuto Robert E.
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