Road structure – process – or apparatus – Apparatus – Screed or drag
Reexamination Certificate
2002-01-16
2004-08-24
Hartmann, Gary S. (Department: 3671)
Road structure, process, or apparatus
Apparatus
Screed or drag
Reexamination Certificate
active
06779945
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to devices for leveling and smoothing a substance such as concrete, particularly when the substance is freshly placed. More particularly, this invention relates to an apparatus for leveling, enhancing the mixture, and smoothing a freshly placed substance such as concrete using a leveling blade, a connecting strip, and a smoothing float. Even more particularly, this invention relates to an apparatus for leveling and smoothing a freshly placed substance such as concrete in one step by a single operator.
There are many tools used today by concrete workers to smooth a surface of concrete. Typical smoothing tools, for example screeds and trowels, allow workers to smooth the surface of freshly poured concrete or similar viscous hardening substance. Concrete-working tools range from the very simple, hand-held variety to complex motorized units that use means for vibrating at least a portion of the tool to aid in settling the concrete. Concrete-smoothing methods can involve such aids as rails constructed along the edges of the concrete project that are fitted with a screed that is moved across the rails. The following patents provide examples of the current art in concrete-working tools and methods.
U.S. Pat. No. 5,727,279 discloses a tool for grading, leveling, and sealing wet concrete. The grading head is triangular, hollow, made of aluminum, floats on top of the wet concrete, and is attached to a long handle. The head is attached to the handle through an attachment block. There are also support members that maintain the head's position with respect to the handle. In this invention, the angle between the leg of the triangular head that accomplishes leveling and the leg that performs the smoothing function cannot be varied to accommodate surface-sensitive smoothing. Also, there is no way to vary the material of which the smoothing surface is constructed, allowing for both drawing up the paste in the mixture and smoothing in one leveling cycle.
U.S. Pat. No. 4,397,581 discloses an aluminum hand trowel/bull float that combines features of grooving, leveling, and smoothing in one tool. The float has a handle that can be lengthened and the angle of the handle with respect to the float can be adjusted so that a worker can level the concrete at close range or from a distance. The moving and shifting of concrete by means of this device in accomplished through front and back walls vertically extending from the surface of the float. This device also accommodates weights. As in the previous invention, the angle between the leveling surface and the smoothing surface is constant, and there is no variation of materials possible to accommodate drawing up of paste from the mixture.
U.S. Pat. No. 4,723,869 discloses a semi-rigid, yet flexible, blade assembly made of sheet metal or plastic with a long handle and ribbed reinforcement. This device is intended to be used with weights attached and is designed so that the edges of the blade are allowed to flex vertically during the leveling process. This device is geared for leveling, not smoothing. Leveling and smoothing would be a two-step process using this device. This device cannot accommodate a means for vibration.
U.S. Pat. No. 5,984,571 discloses a vibrating screed that permits selective adjustment of the angle between the axis of a rotatable eccentric and the plane defined by the bottom of the screed plate to vary the relative vertical compaction and horizontal smoothing oscillation movement imparted by the eccentric. The screed includes a frame, motor, an eccentric driven by the motor, a screed plate, and a pair of locking hinges. This device contains a handle-mounted throttle for adjusting the motorized vibration and other automatic features. This device is relatively complex for the one-person cement-leveling job. It allows for changes in horizontal and vertical orientation of the leveling blade, and automatic vibration. This device does not accommodate the drawing up of the paste.
U.S. Pat. No. 5,980,154 discloses a manual screeding system for use in leveling freshly poured concrete that includes a frame for providing structural integrity to the screed. The screeding system includes handles, attached to the frame, for manually holding and manipulating the screeding system during the screeding process. A support, attached to the frame, is provided for preventing the screeding system from rotating about the handles during the screeding process. The support is structured to engage the forearms of the user when the screeding system is in use. A pair of bracket assemblies is provided for securely holding a screed board to the frame. This system requires another structure to accomplish leveling and smoothing of the concrete surface, and does not accommodate mixture enhancement as described above. There is no means for vibration possible with this device.
BRIEF SUMMARY OF THE INVENTION
The present invention, in its most simple embodiment, is an apparatus for the leveling and smoothing of a substance such as concrete. The apparatus includes a leveling blade operated in conjunction with a smoothing float, the leveling blade crossing the material in advance of the smoothing float, and both being pulled, perhaps by a shaft-like handle, so that the operator can, using the handle, smooth a floor surface while standing erect. The invention levels and smoothes a substance such as concrete by striking off excess substance using a leveling blade while simultaneously smoothing the surface with a float that follows the leveling blade. At the same time, the apparatus draws up the paste from the substance mixture.
The apparatus of the present invention includes a smoothing float having (1) a smoothing surface that opposes a blade-connecting surface, (2) a leveling blade that has an edge formed between two opposing surfaces: a float-connecting surface and a pull-connecting surface, (3) a resilient connection between the float-connecting surface and the blade-connecting surface; the resilient connection binds the leveling blade to the smoothing float, and allows the angle between the leveling blade and the smoothing float to vary, and (4) a pulling means, which may be a handle, that has two ends; one end is for a pulling force, perhaps an operator or a piece of machinery, to grasp and pull the apparatus, the other end is connected to the leveling blade. Further, the leveling blade and float can be resiliently connected as follows: they can both be connected to three of the sides of the connecting strip by any form of a means for connecting. The means for connecting may include sheet rock screws, bonding adhesive, and other connecting devices. The pulling means is mounted directly to the leveling blade or to a mounting bracket connected to the leveling blade. The pulling means may consist of a single length or include means for extension. The mounting bracket may be of a fixed variety or include means for articulation. The mounting bracket and the pulling means may be of generally known types in the art.
Most preferably, the present invention is comprised of a leveling blade and a float made of aluminum or rubber. The resilient means of connection between the float and the leveling blade, namely the connecting strip, may be any resilient material including wood, magnesium, rubber, and a variety of plastics. The preferable material of the connecting strip has a cement-pulling tendency. Most generally, the invention may be constructed of any suitable materials.
In operation, the apparatus pulling means attached to the leveling blade allows the operator or a piece of machinery to pull the leveling blade forward followed by the float. The leveling blade levels and smoothes an underlying substance such as concrete by striking off excess substance with the leveling blade. Simultaneously, the float follows, smoothing the substance following the leveling blade. If the present invention is used with concrete, the connecting strip can be made of material that has a property of causing cement paste in the concrete to flo
Dishong George W.
Hartmann Gary S.
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