Wide Swath Offset Concrete Screed

This application is a continuation of U.S. patent application Ser. No. 17/573,605 filed Jan. 11, 2022 which was a continuation-in-part of U.S. patent application Ser. No. 16/689,056 filed Nov. 19, 2019 which was a continuation of U.S. patent application Ser. No. 16/197,257 filed on Nov. 20, 2018 which was a continuation of U.S. patent application Ser. No. 15/621,804 filed on Jun. 13, 2017 which was a continuation-in-part of U.S. patent application Ser. No. 14/877,805 filed on Oct. 7, 2015, the disclosure of these applications being incorporated herein by reference in their entireties; and this application claims priority from and the benefit of the earliest filing date of these applications.

The present invention relates to a wide swath offset concrete screed for leveling poured concrete within a form, and more specifically systems and methods of making and using a wide swath concrete screed that doesn't require mechanical vibration.

Wet concrete generally arrives on-site in a concrete truck for pouring into the forms to define the desired level when the concrete dries. When the concrete is poured from the chute of the concrete truck the result is generally mounds of wet concrete—often called mud or slurry—piled above the level defined by the top edges of the forms. The slurry must be promptly leveled as it is poured, before it hardens or sets. Typically, the leveling is performed by a screed—a specialized tool that traverses the forms. Smaller pours such as a sidewalk can be leveled with a hand screed that one or more workers drag along the forms to level the mounds of wet concrete. It is not feasible to use hand screeds for larger pours such as parking lots, road surfaces, the floors of buildings or other such large, flat concrete surfaces. The weight of the concrete being pulled off is generally too great for workers to use hand screeds.

Larger concrete projects are poured in strips that may be ten to twenty feet wide, but can even be thirty or more feet wide. Conventional mechanized concrete screeds are used to level the strips of concrete. One such type of conventional mechanized screed involves the use of a vibrating screed. A small gasoline engine is mounted on the screed with a rotating offset weight designed to impart vibration to the screed as it is dragged across the wet mud. Some conventional vibrating screed implementations require one or more workers just outside the forms to push and guide the screed along the top of the forms as the engine vibrates the screed. The vibration is required to prevent small pebbles from momentarily catching on the front edge of the screed and dragging small holes in the surface of the slurry before the pebble finally passes under the screed. The vibration aids in pushing the small pebbles down into the slurry, allowing the conventional vibrating screed to pass over the pebbles with minimal perturbation to the surface of the wet concrete. A gasoline or diesel engine is required for this conventional solution, thus requiring one or more workers to attend to the engine as the device is started and stopped many times during the course of a day's pouring. Due to the dirt and dust present at the work site it can be difficult to keep the conventional vibrating screed from breaking down during a pour, often necessitating emergency repairs to keep pouring while concrete trucks are standing by ready to unload their wet concrete.

Published U.S. Patent Application 2009/0092444A1 to Schoen (hereinafter “Schoen”) describes a conventional wide swath motorized screeds. The Schoen screed features a screed mechanism attached to a skid loader that a worker operates to pull the mounds of wet concrete and create a level surface. Another implementation of a conventional mechanical screed involves attaching a conventional vibrating screed to a front end loader or skid loader. Mounting a conventional vibrating screed on a front end loader eliminates the need for concrete workers to push the screed along as it vibrates.

Embodiments disclosed herein address drawbacks of the conventional mechanical concrete screeds. The presently disclosed embodiments save considerable labor in the process or leveling wet concrete. For example, a conventional screed device requires a crew of six or more workers to pour and finish the concrete surface. Using the various embodiments disclosed herein a similarly sized pour of concrete could easily be handled by three workers a savings of at least 50% in labor costs.

Various embodiment disclosed herein provide methods and systems for making and using a wide swath offset concrete screed apparatus for screeding wet concrete slurry. The apparatus includes a cross support bar, an attachment mechanism for attaching the cross support bar to a liftable arm of a motorized vehicle, and lateral support bars for attaching a screed bar to the cross support bar. The screed bar is positioned offset from the motorized vehicle used to operate the screed, allowing the motorized vehicle to drive outside the forms.

Typically, to pour a swath of concrete a pair of longitudinal forms is assembled at the desired level of the concrete. The longitudinal forms run along the sides of the swath, and an end form may be positioned between the longitudinal forms, defining the end of the swath. Once the wet concrete slurry is poured within the longitudinal forms—generally, one truckload at a time—the leveling is performed by running a screed along the top of the longitudinal forms to smooth the swath of concrete between the forms. The term “leveling” is used to describe the smoothing process using a screed. The result of “leveling” the wet concrete slurry with a screed produces a relatively flat surface between the forms. This flat concrete surface that results from leveling with a screed may, or may not, be level with respect to the earth's surface. For example, the floors of buildings, parking lots and other concrete surfaces are often designed to have a slight degree of slope in order to allow water to run off. Concrete surfaces are often poured to slope between ⅛ inch per foot to up to ⅝ inch per foot, with ¼ inch per foot being a common value. Therefore, the term “leveling” as it is used herein implies that the surface of the concrete is smoothed to conform to a flat surface between the top edges of the forms, and may include a built in amount of slope rather than being perfectly level relative to the earth's surface. That is, leveling wet concrete means to smooth the surface to be relatively flat across the tops of the two forms the concrete was poured into. In situations where multiple swaths are being poured to form a wide expanse of concrete, it is often the case that the previously poured swath of concrete, now hardened, is used in place of the forms on one side of the next swath to be poured. The hardened concrete serves as a “form” on one side as the new swath is being poured and leveled. In such cases where a swath is being poured beside another, previously poured swatch, a spacer may be used to compensate for the level of freshly screeded concrete being slightly lower than the level of the underside of the screed, as discussed further in conjunction with.

Motorized screeds—that is, a screed mechanism attached to a skid loader or other motorized vehicle—are often used to save time and labor in pouring swaths of concrete. The present inventor recognized several drawbacks inherent in the designs of conventional mechanized screeds, for example, the Schoen screed of Published U.S. patent application Ser. No. 20/090092444A1. One major drawback of it is that the front end loader of the conventional Schoen screed must be driven within the forms directly ahead of the wet concrete being leveled. Nearly all concrete is poured over one or more layers of iron rebar lying on a surface of sand which acts to strengthen and reinforce the concrete. Using the conventional Schoen motorized screed requires the skid loader to be driven over the rebar, pushing it into the layer of sand beneath the concrete and often causing deformities in the rebar. This would render the rebar useless unless remedied before the concrete dries. Thus, workers must be positioned between the conventional Schoen screed and the wet concrete being leveled to pull the rebar up out of the sand. Another disadvantage of the Schoen device that the present inventor recognized involves the end form for the pour. An end form is the form at the end of the swath being poured, for example, to define the edge of a building pad or parking lot. A skid loader cannot be driven over the end form without destroying it. So, in order to use the Schoen device the end form must be assembled as soon as the front end loader of the conventional Schoen screed passes that point. Alternatively, some sort of makeshift removable bridge or ramps could be constructed over the end form, allowing the front end loader of the conventional Schoen screed to be driven up over the end forms without damaging them. These, and other drawbacks of the conventional screeds recognized by the present inventor, are overcome by various embodiments disclosed herein.

is an oblique view of a wide swath offset concrete screedaccording to various embodiments disclosed herein. The wide swath concrete screed is mounted on a motorized vehiclesuch as a skid loader, an extension loader, a front end loader, a tractor, a backhoe, a truck, a tractor, a tracked loader, or other such motorized vehicle. The wheeled vehiclehas a liftable mechanical armof sufficient strength to hold the screed assembly with the capability of lifting it up and down. The offset wide swath concrete screedaffords the advantage of being mounted to the side of motorized vehicle—that is, the concrete screedis mounted such that the screed baris offset to the side of the motorized vehicle. To be considered “offset” the screed baris positioned outside the wheels (or track, if a tracked vehicle). Typically the screed baris parallel to the direction of an axel of the motorized vehicle. The screed barmay be referred to as a fixed screed barto differentiate it from roller screed bars discussed in the ensuing paragraphs. This offset mounting configuration allows the motorized vehicleto be driven along the outside of concrete forms. This is a significant advantage over conventional mechanized screeds that drive within the concrete forms. In this way the various embodiments disclosed herein do not push the rebarinto the sand as the concrete is being screeded since the vehicleis driven outside the forms rather than inside the forms on the rebar. Moreover, the various embodiments of the wide swath concrete screed disclosed herein are able to screed concrete right to the end of the longitudinal forms without damaging the end form. Various embodiments of screeds disclosed herein are also capable of being mounted directly in front of the motorized vehiclefor those situations when there is insufficient room alongside the formsto drive the motorized vehicle, e.g., when the last swath being poured is up against a fence, wall or building.

The liftable armof the motorized vehicleallows a user to lift the concrete screedup and down as needed during the pour. Since the concrete screedmay weigh 300 pounds or more, with an outer end that extends beyond the motorized vehicleby several feet more the width of the longitudinal forms, the liftable armmust have sufficient strength to withstand the rotational force due to the weight of the concrete screedhanging out to the side.

The offset concrete screedincludes a connection mechanismor structure for attaching the cross support barto the motorized vehicle. In some embodiments the connection mechanismincludes two metal plates bolted together to clamp down on the cross support barand hold it securely to the liftable arm. In some embodiments the connection mechanismincludes U-bolts, or metal cables, to secure the cross support barto the liftable arm. In other embodiments the connection mechanismincludes an adapter to fasten the cross support barto a fork lift attachment, or a three-point hitch, of the liftable arm. In yet other embodiments the connection mechanismattaches to a hydraulic cylinder to affix the cross support barto the motorized vehicle. Regardless of the configuration, the various embodiments of the connection mechanismincludes structural means for attaching the cross support barto the liftable armof the motorized vehicle, either in a stationary position or in a manner capable of hinging. The motorized vehicle may be equipped with a swiveling liftable arm capable of swiveling to the side (e.g., horizontally perpendicular to direction of movement) far enough to reach out over the forms, thus eliminating the need from a cross support bar. In such embodiments the swiveling liftable arm is connected directly to the lateral support bars, either directly or using a specialized bracket, without need of a cross support bar that extends beyond the forms. In some embodiments the specialized bracket, or other means for attaching the lateral support bar(s) to the swiveling liftable arm of a motorized vehicle, may extend beyond the forms as far as the screed bar extends.

A screed baris configured to pull the mounds of wet concrete slurry deposited within the forms by a concrete truck. In this way the slurry is leveled during a pour by the action of the motorized vehicle driving back and forth on the outside of forms. The screed baris pulled by lateral support bars, which in turn, are connected to cross support bar. The motorized vehiclemay be positioned to push the cross support barin the direction of screeding movement, as shown in. Alternatively, the motorized vehiclemay be positioned on the other side of the cross support bar(ahead of it) so as to pull the cross support barin the direction of movement. In either case, the screed baris dragged behind the cross support baras the wet concrete slurry is being screeded. This dragging motion prevents the screed barfrom jamming down or catching on the forms as it is moved along.

In at least one embodiment the two lateral support barsare replaced by a single wide lateral support bar spanning the width between the lateral support barsdepicted in. The single wide lateral support bar may be fabricated from a reinforced steel or iron sheet, or other material of sufficient strength drag and support the screed bar, e.g., composite or synthetic sheet material or corrugated panel. The single wide lateral support bar helps prevent one side of the screed barfrom riding up over a mound of wet concrete while the other side remains on contact with the form. One or more viewing holes may be cut or molded in the single wide lateral support bar to provide the driver of the motorized vehicle with a better view of the wet concrete slurry just ahead of the screed bar.

The screed baris of sufficient length for both ends to rest on the longitudinal forms. Typically the screed baris slightly wider than the distance between the longitudinal formsso that the screed barextends beyond the longitudinal formsby a few inches. In a typical implementation the screed barmay be from 6 to 24 inches longer than the distance between the longitudinal forms. In other implementations the screed barmay be any length from the same width as the outer width of the forms up to ten or more feet wider than the width of the forms. There is no set limit as to how much wider the screed baris as compared to the width of the forms. However, since workers often walk or stand just outside the forms it tends to be more safe and convenient for the width of the screed barto extend beyond the forms by no more than a few inches on each side. For example, in some embodiments the screed baris of a sufficient length so that it extends beyond the forms by 8-10 inches on either side to keep the screed from falling inside the forms.

Depending upon the application, the swatch of concrete may be of any given width. For some uses the width of the concrete swath is not important. For example, a large expanse of concrete such as a parking lot may sometimes be poured in strips or swaths of any width, up to the maximum width, that is desired by the prime contractor or suitable for the situation. However, some applications (and some builders) require that the concrete be poured in a specific width swatch, e.g., 12 feet, 15 feet, 20 feet, 25 feet, 30 feet, or other such swath widths. To accommodate these specific swath widths, the concrete screedmay be equipped with various lengths of screed bar. In some embodiments, the length of the screed baris fixed, and bars of various lengths are swapped out to accommodate the required swath width. Other embodiments of the screed barare configured so that the length of the screed barmay be adjusted to suit the distance between the formsor other parameters. This may be achieved by providing a telescoping screed bar, or by providing removable sections of the screed barwhich may be swapped out to achieve the desired length.

The screed baris held by two or more lateral support bars, which in turn, are connected to a cross support bar. To smooth out the mounds of wet concrete the motorized vehicleis typically positioned to push the cross support bar. However, the cross support baris configured to pull the screed baralong, dragging the wet concrete to a level format. This pulling action aids in preventing the screed barfrom gouging into the longitudinal forms, thus making the screed baroperate more smoothly as the wet concrete is being leveled.

is an oblique view depicting wide swath offset concrete screedin use as wet concrete is being poured. The figure shows the point in time when the wet concrete from one truck has already been leveled out, the screed barhas been lifted up out of the way, and motorized vehicle of(not shown) of the concrete screedis backed up so as to allow another truckload of wet concrete to be poured.

As shown inthe lateral support baris attached to the cross support barby a hinge assemblyconfigured to hinge upward as the screed barcomes to rest on forms. The hinge assemblyprevents the screed barfrom hinging downward more than a predetermined amount, in order to lift the screed baroff the forms as shown in. The predetermined amount—defined as the support bar angle—is measured at the point where the motorized vehicle's liftable armhas been lowered such that the screed barjust touches the forms. That is, the support bar angle is the angle between the axis of rotation of the hinge assemblyand the bottom front edge of the screed barwhen it is lowered to the point of just touching the forms. It should be clear from this that the the support bar angle does not depend upon the shape of the lateral support bar. At this point, if the cross support baris raised it will lift the screed barup since the hinge assemblywon't hinge downward past the support bar angle. On the other hand, if the cross support baris instead lowered the hinge assemblywill hinge upward since the screed baris resting on the forms. Various embodiments are configured so the lateral support barhangs downward at a support bar angle of from 1 degree to as much as 60 degrees, or any angle within these limits, with a hang angle of 15 degrees being typical. The lower limit of the support bar angle, 1 degrees, is determined by the distance between the axis of rotation of the hinge assemblyand the bottom surface of the cross support bar, and depends on the length of the lateral support bar.

is a close up view depicting details of one embodiment of the hinge assemblybetween the lateral support barand the cross support bar. Other embodiments may use like types of structures configured to provide a hinging action such as an ordinary hinge, a rocker arm assembly, a trough holding the ends of lateral support barsand flexible cable controlling the maximum hinge angle or support bar angle, a ball joint, or other like types of hinging structures. The hinge assemblyconnects the lateral support barto the cross support bar. The hinge assemblyallows the lateral support bar, and in turn the screed bar, to hinge upward as the device is lowered onto the longitudinal forms. As discussed above, the hinge assembliesprevent the lateral support bars, and in turn the cross support bar, from hinging downward by more than a predetermined amount, defined as the support bar angle. In this way the motorized vehiclecan lift the screed barup in the air.

The conventional Schoen screed of Published U.S. patent application No. 20090092444A1 features a mounting pocketthat prevents armfrom rotating too far downward. Such a pocket/arm assembly could be used with embodiments disclosed herein as a hinging mechanism. However, the present inventor recognized certain drawbacks with the Schoen pocket/arm assembly. Namely, the pocket tends to retain wet concrete and small pebbles during the course of a working day. This, in turn, makes the pocket difficult to clean upon completion of a work day. At the end of each day, and perhaps even during the course of the day, the barmust be rotated upward out of pocketin order to clean out all the accumulated concrete and pebbles. If the pocketof the Schoen device is allowed to dry overnight without being thoroughly cleaned it will sometimes freeze in place as the bits of remaining concrete dry and harden. The Schoen device can also freeze up while it is being used if a small pebble or bit of concrete becomes lodged between the barand pocket. The hinge assemblyovercomes these drawbacks since it is a more open design which does not tend to accumulate pebbles and wet concrete. The hinge assemblyis easier to clean with a hose and water since there is no pocket for pebbles and wet concrete to gather in during the course of a day.

In various embodiments of the offset concrete screed, the hinge assemblyis rotatably connected to cross support barby a pin. By “rotatably connected” it is meant that the hinge assembly is connected in a manner that allows it to rotate, or hinge, about an axis. In some implementations the pinpasses through, or is otherwise connected to, a pin holder bar. In other embodiments the pinis connected directly to the cross support bar. The pinmay be a bolt of sufficient diameter (e.g., ⅜ to 1 inch) for supporting the weight of the lateral support barsand screed bar. The bolt may be kept in place with a nut, or two nuts tightened against each other, and washers to aid in preventing wear on the bolt and hinge assembly. In other implementations a hinge pin, a metal rod, or other like type of pin may be used as the pin.

In some embodiments one or more springsare connected to some point on the support bar assembly to provide more downward force than the weight of the screed bar. The additional downward force aids in preventing the screed bar from riding up over the wet concrete slurry. Typically, the springsare configured to be removable so that weaker or stronger springs—or multiple springs—can be attached, as needed. In this way the user is able to adjust the downward force to accommodate the conditions of the pour. Some embodiments use compression springs to push downward on the support bar assembly. In other embodiments leaf springs are used to provide the downward force.

The hinge assemblyis typically configured so that it comes to rest against cross support barwhen the offset concrete screedis raised up in the air. The hinge assemblyhinges upward in response to the concrete screedbeing lowered so that the screed barrests on forms. This allows the screed barto ride along the top of the formswithout damaging the forms. The hinging action also allows the screed barto ride up over an overly large mound of wet concrete to avoid putting too much horizontal strain on the screed barand concrete screed. If the screed barrides up over an overly large mound of wet concrete the user can simply raise the offset concrete screedup in the air, back up the motorized vehicle, and take one or more additional passes at smoothing the large mound of wet concrete. Since embodiments of the offset concrete screedallow the motorized vehicleto be driven off to the side rather than over the rebar, the user can efficiently make several passes without need to have workers reposition to rebar after each pass, as is required for conventional motorized screed devices.

depicts the wide swath concrete screedbeing used to level the wet concrete slurryusing a previously poured swath of concretein lieu of a form on one side. In pouring large expanses of concrete for a parking lot or building pad it is often the case that the swaths are poured side by side with the previous day's swath acting as a form on one side of the current pour. The very first swath poured requires a formto be set up on each side of the swath to be poured. For each subsequent swath poured after the previous swath has hardened (e.g., a day or more later) only one formneeds to be erected. The previously poured swath, now hardened, acts as a form on the other side to contain the newly poured wet concrete slurry.

One issue with using a previously poured swath in lieu of a form is that the process or screeding wet concrete results in a screeding process delta in which the level of the concrete is slightly lower than the level of the forms (or the form and the previously poured swath being used as a form). For example, a screeded concrete surface may end up ¼ inch or so lower than the forms on either side—that is, have a screeding process delta of ¼ inch or so. This is because the wet concrete slurry contains small pebbles and gravel in it. The screeding process delta results because the screed bartends to push some of the small pebbles and gravel in front of it, causing the screeded surface of the wet concrete slurry to be slightly lower than the bottom surface of screed bar, e.g., ¼ inch or so lower. This can be somewhat troublesome if the concrete is being poured in long swaths alongside a previously poured swath—now hardened—from the previous day. If the screeding process delta was not compensated for and the formwas erected to be level with the previously poured swath, each newly poured swath would end up being ¼ inch or so lower than the previously poured swath beside it. If a number of swaths were poured this way the result would be that each swath would be ¼ inch or so lower due to the screeding process delta of each swath. In order to avoid this, it is desirable to provide formsfor the new swath to be poured that are at a level slightly higher than the previously poured swath to its side by an amount equal to the anticipated screeding process delta. The slightly higher level of the formcompensates for the lower level of finished concrete due to the screed barpushing small pebbles and gravel in front of it. However, if the previously poured swath (which has hardened) is being used as one of the formsthen it is not possible to adjust the height of the previously poured swath to compensate for the screeding process delta. To this end, various embodiments use a screed bar spacer affixed to the bottom of screed baron the side of the previously poured swath in conjunction with the formbeing constructed slightly higher than the level of the previously poured swath.

also depicts a screed bar extension. The cross section of the screed bar extensionis typically the same as the screed bar, with a slightly smaller cross-sectional portion that fits into the end of the screed bar. One or more holesmay be provided for boltsused to secure the screed bar extensionto the screed bar. The boltspass through holesand tighten into threaded holes.

depicts the wide swath concrete screed with a leveling auger. The augeris rotationally powered by a power unit. The power unitmay be similar to power unitdepicted in. Power unitmay be implemented in various forms, including for example, a gas or diesel engine, an electric motor, a hydraulic motor, a rotating shaft connected to the power take-off of the motorized vehicle, a rotating linkage connected to the engine of the motorized vehicle, or other like type of power unit known to those of ordinary skill in the art. The power unitmay either be connected to the cross support bar, or in other implementations, may be connected to one or more of the lateral support bars. The power unitmay be controlled by a user to controllably rotate the augerat varying speeds. The augermay be rotated in one direction to push the wet concrete slurry towards the motorized vehicle, and may be controlled to rotate in the opposite direction to push the wet concrete slurry away from the motorized vehicle.

depicts embodiments 500 and 550 of an optional screed bar spacer and subgrade screederattachments that may be affixed to the screed bar. As shown in the figure, the screed bar spaceris affixed to the end of the screed barresting on a previously poured concrete surfaceto compensate for the screeding process delta. The screed bar spaceris a removable attachment with a predetermined thickness that compensates for the level of freshly screeded concrete being slightly lower than the level of the underside of the screed bardue to small pebbles and gravel being pushed in front of screed barduring the screeding process. A user simply taps the screed bar spacerinto position within the screed bar, and it is held in place by friction. To remove the screed bar spacer, the user merely taps it back out. The screed bar spaceris held to the bottom side of screed baron the end that rides across the swath of previously poured, hardened concrete. Since the level of the freshly screeded concrete will be lower by a slight amount than the bottom of the screed bardue to the screeding process delta, the screed bar spacerallows the screed barto pass over the newly poured concrete at a level slightly higher than the desired level of the finished concrete surface to compensate for the screeding process delta. In this way, the newly screeded concrete will end up at approximately the same level as the previously poured concrete swath adjacent to it.

The wide swath offset concrete screedmay be provisioned with screed bar spacersof various thicknesses, depending upon the anticipated amount of screeding process delta—that is, the amount that the newly poured concrete is anticipated to be lower. The anticipated amount of screeding process delta depends upon the characteristics of the wet concrete slurry such as the size of the pebbles and gravel in the wet concrete slurry, how wet the concrete slurry is, the temperature of the wet concrete slurry, etc. Since a given contractor may order wet concrete slurry many times from the same concrete supplier, the contractor will generally get a feel for the amount of screeding process delta to expect from a particular concrete provider for a given grade of concrete. A screed bar spacerfor use with the various embodiments may have a predetermined thickness of as little as 1/16 inch or as much as ¾ inch, or any value in between, depending upon the characteristics of the wet concrete slurry resulting in screeding process delta. A typical thickness for a slab of concrete 8 inches thick is ¼ inch. In various embodiments the bottom side of the screed bar spaceris smooth with rounded corners in order to push the pebbles and gravel of the wet concrete slurry underneath it during the screeding process. This aids in preventing the pebbles and gravel from scraping along the surface of the wet concrete slurry before they pass beneath the screed bar spacer. In addition the screed bar spaceris configured to be smooth with rounded corners aids to avoid gouging or scoring the concrete surface that it rests and slides upon.

depicts another screed bar spacer embodiment—the screed bar spacerwhich is configured with a wheel that rolls along the previously poured concrete surface. The screed bar spaceris particularly useful when the previously poured concretehas not yet hardened sufficiently to avoid scoring the surface. The screed bar spacerslides into screed bar, and is tightened into place with a compression bolt. Moreover, the screed bar spacermay be configured to be adjustable by providing an elongated slot either for boltor for a bolt at point.

also depicts a subgrade screeder attachment. To preparing a pour site the contractor generally deposits gravel, sand or pebbles, or some other subgrade material, between the longitudinal forms. It is important to have a uniformly flat, level subgrade surface to pour the wet concrete slurry on, in order to ensure that the resulting concrete pad is of a uniform thickness. According to conventional methods, the subgrade material is graded and leveled by hand with shovels or rakes. These conventional methods of preparing the subgrade are quite a labor intensive and must be performed prior to pouring the concrete. It generally takes at least a couple—or even several—manual laborers working to smooth and level the subgrade material by hand, and it is nearly impossible to create a uniformly flat, level subgrade surface. The embodiments disclosed herein overcome aid in cutting down the manual labor required to prepare the subgrade materials by hand, while at the same time drastically increasing the precision of the subgrade leveling process.

The subgrade screeder attachmentdepicted inattaches to the screed barusing one or more bolts. Alternatively, the subgrade screeder attachmentmay be affixed to the screed barusing pins, clamps, cables, chains, or other like type of structures for affixing the subgrade screeder attachmentin place on the screed bar. In other embodiments the subgrade screeder attachmentis attached to the screed barwith a hinge mechanism so that it can be hinged upward out of the way when not in use. The depth that the subgrade screeder attachmentextends below the lower level of screed baris adjustable in order to equal the desired thickness of the concrete pad being poured. In the embodiment depicted inthere are a series of holes that allow the subgrade screeder attachmentto be set at various depths, thus creating concrete pads of various thicknesses. In other embodiments the subgrade screeder attachmenthas an elongated hole, or slot, to allow adjustment up and down to create various thickness of a concrete pad.

Typically, the width of the subgrade screeder attachmentis slightly narrower than the width of the longitudinal forms, for example, one to six inches narrower. The screeder attachmentmay be provided in multiple pieces so as to easily vary the width to accommodate the width of the longitudinal forms. The subgrade screeder attachmentis typically made of metal. Aluminum generally provides sufficient strength, and is advantageously lightweight. However, other implementations of the subgrade screeder attachmentmay be made of iron, steel, or other like metals. In some embodiments the lower edge of the subgrade screeder attachmentmay be curved slightly in the direction of screeding movement. The slight curve tends to cut into the loose gravel, sand or pebbles typically used as subgrade material, thus pulling the subgrade screeder attachmentslightly downward to create a smooth, level subgrade surface. In various embodiments the curved portion of the lower edge of the subgrade screeder attachmentis angled from as little as 15 degrees to as much as 90 degrees, relative to vertical. In other embodiments the lower edge of the subgrade screeder attachmentis squared off straight, rather than having a slight curve as shown in.

depicts the wide swath offset concrete screedin a raised position. In some instances the area just outside the forms and just beyond the end of the swath of concrete being poured may have an obstacle such as a fence or building, or otherwise be inaccessible. When this occurs it may not be possible to drive the motorized vehiclevery far beyond the end of the swath of concrete. In such situations it is useful to be able to lift the concrete screedhigh enough to permit a concrete truck to back up close enough to unload the wet concrete beneath the raised screed. Various embodiments of the concrete screedcan be raise high enough to permit wet concrete to be unloaded beneath it, as shown in. For example, depending upon the type of motorized vehiclebeing used, the wide swath offset concrete screedcan be raised to a level of fifteen feet or more. For embodiments using an extension loader as the motorized vehicleas depicted inthe offset concrete screedcan be raised to over twelve feet. This is sufficient height to allow a concrete truck to back up and deliver its load of wet concrete slurry under the offset concrete screed. Other embodiments may raise the concrete screedeven higher, for example, for clearance beneath the screed barof 15 feet or even more, depending upon how far the liftable armof the motorized vehicleis able to extend or rise in the air.

As the liftable armis lowered it is desirable not to slam it into the lateral forms. To aid in this some embodiments include a flow restrictorin the hydraulic line to controllably constrict the flow of hydraulic fluid. The flow restrictortends to slow down the upward and downward movement of the liftable arm, making it easier for a user to ease the liftable arminto position as it is raised and lowered during the screeding process.

depicts a lateral support barconfigured to have a slight amount of curve at point. In various embodiments it is desirable for the underside of screed barto lay relatively flat on the wet concrete slurry and the longitudinal forms. Having the underside of screed barflat aids in keeping it from riding up over mounds of wet concrete slurry as it is pulled along, or gouging into the wet concrete. Further, the flat underside as it is drawn over the wet concrete slurry provides a smoothing effect that helps to produce a smooth, level surface of the finished concrete. At the same time it is desirable to keep the cross support barseveral inches above the formsto keep it from catching on the formsand causing perturbations in the smooth surface of the concrete.

To achieve this—having the underside of screed barflat while the cross support barpasses several inches above the forms—various embodiments of the lateral support barsare configured to have a slight amount of curve. In some embodiments the lateral support barsare gradually curved along their entire length. In other embodiments, the lateral support barsare curved at a particular point, for example, at pointas depicted in. In yet other embodiments, the lateral support barsare angled at a particular point rather than being gradually curved (e.g., a sharp curve). In various embodiments the lateral support barsmay be curved by a lateral support bar curve. In various implementations the lateral support bar curvemay vary from as little as 1 degree to as much as 30 degrees, and may be any value in between these two extremes. A typical value for the lateral support bar curveis 4 degrees. In other embodiments the lateral support barsmay be straight without any lateral support bar curve. In some embodiments the lateral support barsare approximately four feet long. However, the length may be varied depending upon the requirements of the pour and the situation in which it is to be used to be as short as one foot or as long as twelve feet. Using shorter lateral support barswill result in the cross support barbeing positioned closer to the forms. Using longer lateral support barswill result in more downward rotational force on the cross support bardue to the increased leverage. Therefore, in various embodiments the lateral support barsare generally kept within three to six feet, with four feet being a typical length embodiment.

is a flowchart depicting the use of the concrete screedaccording to various embodiments of the invention. Reference is made to the previous figures in the application, including various reference numbers shown in the figures. The method begins at blockand proceeds to blockwhere the user provides a cross support bar. The cross support baris typically connected to the liftable armof a motorized vehicle. The method proceeds to blockfor attaching the lateral support barsto the cross support bar. This is generally done using hinge assemblies. In some embodiments, however, the lateral support barsmay be fixedly connected to the cross support bar, with the lateral support barsthemselves being capable of hinging. The lateral support barstypically have a slight amount of bend in them, e.g., approximately four degrees—that is, 4°+/−10%.

In blockthe screed baris connected to the lateral support bars. Typically, the screed baris fixedly attached to the lateral support bars. However, in some embodiments the screed barmay be connected to the lateral support barsin a manner that allows the screed barto have some play or movement relative to the lateral support bars, e.g., a hinging motion. In blockit is determined whether the longitudinal formsare wider apart than the length of the screed bar. If the screed barneeds to be longer, the method proceeds along the “YES” path to bockfor attachment of one or more screed bar extensionsto the screed bar, and then proceeds to block. If the screed baris of sufficient length for the configuration of longitudinal formsthe method proceeds from blockalong the “NO” path to block.

In blockofit is determined whether the wet concrete slurry is to be poured into forms on either side (e.g., for the first concrete swath to be poured), or a previously poured, now hardened, swath of concrete is to be used on one side of the pour in place of the longitudinal forms for that side. If previously poured swath of concrete is to be used in place of the forms it may be the case that the screeding will result in a screeding process delta in which the level of the concrete is slightly lower than the level of the forms, as discussed previously in conjunction with. If a screeding process delta—that is, a level of the concrete surface slightly lower than the scree bar surface—is anticipated, the method proceeds from blockalong the “YES” path to blockto attach a screed bar spaceror. However, if no screed bar spacer is desired the method proceeds from blockalong the “NO” path to block.

In blockthe user operates the motorized vehicleto screed the wet concrete slurry to a desired degree of levelness. During the screeding process it is sometimes the case that the screed barneeds to be raised, for example, to back the motorized vehicleup or to allow a concrete truck to deliver another load of concrete. If, in block, it is determined that the screed barneeds to be raised the method proceeds along the “YES” path to blockto raise the screed bar(or lower it if it was previously raised). The method then proceeds to blockto determine whether further screeding operations need to be performed. If further screeding is to be done, the method proceeds back to blockalong the “YES” path. However, if the screeding is completed the method proceeds from blockalong the “NO” path to blockwhere the method ends.

Various activities of the method disclosed herein may be included or excluded as described above, or maybe performed in a different order than the particular examples chosen to illustrate the embodiments. For example, it may be the case that the screed bar extension may be attached to the screed bar (block) prior to attaching the screed bar to the lateral support bar (block). Or it may be the case that the screed bar spacer may be attached to the screed bar (block) prior to attaching the screed bar to the lateral support bar (block). The sequence of steps for performing the method of making and using a wide swath offset concrete screed according to the various embodiments disclosed herein may be altered in many other ways as well.

are oblique views depicting embodiments of an up-down offset concrete screed. The present inventor recognized the difficulty of screeding concrete into certain tight spaces—for example, screeding into the corner formed by two buildings, or screeding right up against a building or a wall. In such tight spaces it is desirable to be able to operate the screed as closely as possible up to the limiting obstruction. The embodiments depicted inmake it possible to screed into tight places with only a minimum of finish work to be done by hand.

The up-down offset concrete screed embodiment features two or more vertical support bars. The vertical support barsare designed to move up and down, as needed, during the screeding operation. For example, it may be that the surface outside the forms on which the motorized vehicleis driving is unlevel or bumpy. If the motorized vehiclemoves up or down as it is traveling along, the vertical support barscan move down or up, as needed, so that the screed barmay remain on the forms. In some instances, if there is too much wet concrete slurrybeing pushed the screed barmay ride up over the slurry, leaving an unlevel spot that will require further screeding on another pass.

Each vertical support baris enclosed by a support bar sleevethat allows the vertical support barto move up and down. The end of each vertical support baris larger than the passage dimensions of the support bar sleeveto prevent the vertical support barfrom passing through it. This allows the cross support barto lift up the vertical support barand accompanying screed bar. To aid in the up/down movement the support bar sleeveshave bearings on their inner surface, making it easier for the vertical support barsto ride up and down with the lateral force of the concrete slurry pushing against them. Alternatively, the support bar sleevesmay have small wheels or lubricant instead of bearings.

The vertical support barsare rotatably attached to the screed barallowing the vertical support barsto rotate about an axis, the axis being in the direction of screeding—that is, the axis of rotation is in the same direction as the direction of screeding (e.g., motorized vehicle movement), allowing the direction of rotation to be back and forth at a right angle to the direction of screeding. Similarly, the support bar sleevesare rotatably attached to the cross support bar. In this way, if the motorized vehicledrives on an unlevel or bumpy spot causing the cross support barto raise up or dip relative to the screed bar, the vertical support barswon't bind up if they raise or drop by different amounts. In this way the screeding operation can continue smoothly even though the cross support bardoes not remain parallel with the screed bar. The vertical support barsmay be rotatably attached to the screed barby a tabthat is welded, bolted or otherwise affixed to the screed bar. The tabhas a pin or bolt configured to pass through a hole in the vertical support bar, thus allowing the vertical support barsto rotate relative to the screed bar. In other embodiments (no shown) the tabis affixed to the vertical support barand has a bolt or pin that passes through a hole in the screed bar.depicts details of an embodiment for rotatably connecting the support bar sleevesto the cross support bar.

is oblique cutaway view of an embodiment of the support bar sleevethat rotatably attaches the support bar sleeveto the cross support bar. In this embodiment the hinging mechanism is a boltthat is welded, or otherwise attached, to the support bar sleeveand passes through a holein the cross support bar. The boltallows the support bar sleeveto rotate as needed relative to the the cross support bar. Other hinge mechanisms may be used in various implementations to connect the vertical support barsto either the support baror to the screed bar, including for example, a hinge, a flexible cable, chain links affixed to each part, a shaft and bearings, a trough or slot that supports a shaft, or other like mechanisms known to those of ordinary skill in the art.

depicts an embodiment of a vibrating float assembly configured to be pulled behind the screed bar. In typical implementations the vibrating float assembly is fairly lightweight, for example, weighing between five and twenty-five pounds. However, either heavier or lighter implementations may be constructed, depending upon the dimensions and materials used in the vibrating float assembly itself, and the characteristics of the concrete slurry being floated. Typically, two or more vibrating float assemblies are rotatably affixed to the screed bar. Some embodiments feature only one float affixed to the screed bar. The screed bargenerally is configured to extend beyond the outermost and innermost vibrating float assemblies by at least a few inches. That way, the vibrating float assemblies ride solely on the wet concrete slurry and do not extend quite to the forms. However, in some implementations, the vibrating float assemblies may be configured to be the same width as the screed barso the outermost portions of the vibrating float assemblies ride on the forms just as the screed bardoes.

Each vibrating float assembly has a float pan. The float pansare constructed in various lengths, depending upon the length of the screed barto which they are attached. The float pansattached to a particular screed bardo not all necessarily need to be the same length. For example, a 17 foot screed barfor use on formsthat are 16 feet apart may have an 8 foot float panand a seven foot float panwhich are spaced 2 inches apart. This would leave 5 inches of space between the outmost edges of the float pansand the forms.