FIELD OF THE INVENTION
The present invention generally relates to apparatus and methods for paving material installation and more particularly relates to an improved apparatus for arranging particulate support material and finished paving materials to a desired depth and curvature.
BACKGROUND
Construction of quality walkways, driveways, patios, pool decks, retaining walls and footers, garden perimeters, and other similar structures is a labor-intensive process, typically requiring a number of steps, each step subject to stringent quality and performance requirements. Failure to meet set standards can be frustrating and costly, often causing rework and accompanying delays.
Using conventional construction methods, a trench is first prepared to a depth that allows for specified thicknesses of particulate substrate material that serves as a base, such as gravel, small stones, and sand. This base, in turn, supports the finished paving materials at the proper height, usually at or near ground level. Finished paving materials that are then placed upon the base can include paving blocks, stones, or bricks, or may include poured concrete or other materials. The width of the trench is significantly larger than the width of the finished walkway or other structure due to the need to provide sufficient space for forms to be inserted, manipulated and supported along the sides of the trench. Requiring time and effort that are not seen in the finished product, the process for providing the needed excess width, termed over-digging by those skilled in the construction arts, is inherently wasteful.
To assist in the substrate lay-down process, forms inserted on both sides of the trench are used to contain the particulate substrate materials and also provide a reference for arranging the finished paving material. There are many types of forms that can be used, including wood, plastic and metal forms. Wooden forms can warp undesirably and are not generally reusable, flexible, or easy to install. Plastic forms serve only in lightweight applications and are not sturdy enough to withstand the rigors of the construction environment and not rigid enough to contain heavy materials or bear the weight of a screed. Metal forms are heavy, costly to replace, troublesome to assemble, and relatively inflexible, requiring careful cleaning after use to remove any affixed concrete.
The forms are anchored in place in a number of ways, using devices such as wooden stakes, rebar, or metal stakes devised for the purpose of anchoring forms so that they remain in place as the structure is assembled. Forms are fastened to the anchors using fasteners such as clips, nails, and spacers, for example.
Leveling the forms along any section of a walkway or other structure can be a difficult task. Mistakes or tolerance errors can be additive, further complicating the leveling process.
Once the forms are set in place, the trench or gap is leveled. The term “level” does not imply that the surface of the trench need be completely flat; the term “level” is used to denote creating a smoothed continuous surface without significant high or low areas to allow depositing a layer of substrate at an essentially uniform depth.
When the dirt in the trench has been leveled, the particulate material is deposited between the forms and also leveled. To achieve a uniform depth of material, the substrate material is typically tamped down with a vibratory plate compactor or by a hand compactor. In practice, application and leveling of the substrate material is accomplished by dumping or by sifting the material into the prepared trench from wheelbarrows or other construction machinery such as front loaders. The volume of material that is dumped at any one time is calculated to spread somewhat evenly and reduce excessive raking and handling.
Using the example of a walkway, gravel is deposited as a first or substrate layer. This is then spread and leveled. This process can begin and be assisted with construction machinery, but, as it progresses, typically requires hand leveling with rakes and screed bars to the desired depth. To provide a solid base, the gravel is tamped down with a vibratory plate compactor or by a hand compactor. The cycle of depositing material, spreading, and tamping is repeated with stone dust and sand or other particulates as required, until the surface is properly conditioned for bricks or other finish materials. When all the desired layers are in place, the finished layer of paving blocks, bricks or concrete is put in place to complete the walkway.
Although the process of surface preparation for a walkway or other structure is straightforward, the preparatory steps to prepare the support substrate can be challenging. In practice, these steps are often redone, since accurate leveling at the desired depth for each layer is difficult. Thus, there is a need for improved apparatus and methods for preparation and conditioning of a support base for walkways, driveways, patios, pool decks, retaining walls and footers, garden perimeters, masonry, and other similar structures.
Proposed solutions for installation of materials for a walkway or other structure appear to be less than satisfactory. For example:
- (i) U.S. Pat. No. 6,866,239 to Miller et al. discloses a form assembly for forming a concrete structure during drying of the concrete. The form assembly is an elongated plastic form having a front wall for engaging the concrete, and a rear wall. The front wall is spaced apart from the rear wall to define a pocket for receiving at least one connecting member. The connecting member is secured in the pocket to project a distance beyond an end of the form. A slidable stake holder may also be provided to slide in a C-shaped pocket in the form. The stake holder has right and left flanges that abut against or engage the rear wall. At least one preformed nail hole is provided in each of the right and left flanges. The forms do not indicate desired depth of materials. Connecting members secured in the pockets render the form inflexible at the joint between forms. Unfortunately, the distance from the front wall of the form to the aperture in the sliding stake holder for holding a stake is fixed, making it difficult to set distance between forms on opposite sides of the walkway, complicating lateral placement of the form with the stake accurately placed. Additionally, the sliding stake holder is not fixably engaged with the form by a connector screw or clamp; as a result, sliding, possible while particulate materials are being added between forms, can result in errors.
- (ii) U.S. Pat. No. 7,131,624 to Bogrett teaches flexible forms for creating landscape edging. However, stakes or positioning brackets used to secure the forms are not reusable, and additional spacers are needed to maintain the distance between forms, making it difficult or impractical to place paving blocks. Joining extensions are created from the same material as the forms and are not intended to be reusable and do not appear to facilitate accurate longitudinal adjoining of forms.
- (iii) U.S. Pat. No. 6,021,994 to Shartzer teaches a flexible form for use in pouring concrete. Rigid core members are added to maintain strength but removed when flexibility is desired. Stakes protrude through the forms and connection to the form is made only via the rigid core members with nails, complicating the task of positioning the forms. Since the rigid core members are removed when the forms are bent, however, securing the stakes to the form is not possible.
- (iv) U.S. Pat. No. 4,340,351 to Owens teaches a screed fabricated in modular fashion from a plurality of interconnected, separable frame units. Modular sections forming the screed can be connected to provide a convex or concave screed depending on the shape of the desired surface. However, the screed formed from modular sections is a complicated assembly, difficult to fabricate, and does not provide adjustment appropriate to the desired depth of layers of particulate material.
There exists a need to improve the quality of tools used in creating layers of material for supporting particulate and finished paving materials which eliminate much of the expertise required for substrate preparation and reduce unnecessary rework.
SUMMARY OF THE INVENTION
Embodiments of the present invention address the need for improved apparatus and methods for depositing and preparing surface particulate, stone, bricks, concrete, and related materials for paving installation.
In accordance with one aspect of the present invention there is provided an apparatus for installation of paving materials, the apparatus comprising a screed that is configured to extend across a gap between first and second forms, wherein the first and second forms are substantially piecewise parallel with respect to each other, wherein the screed has at least a first section that is coupled to a second section, and wherein the screed has a first height adjusting member with a first seat surface for slidable contact along the first form and a second height adjusting member with a second seat surface for slidable contact along the second form and wherein the first and second height adjusting members are each adjustable to set the height and angle of the at least first and second sections of the screed within the gap.
From an alternate aspect, embodiments of the present invention provide an apparatus for installation of paving materials, the apparatus comprising a screed that is configured to extend across a gap between first and second forms, wherein the first and second forms are substantially piecewise parallel with respect to each other, wherein the screed has:
- (i) at least a first section that is coupled to a second section;
- (ii) a first height adjusting member within a first cavity and having a first seat surface for slidable contact along a first contact surface of the first form;
- (iii) a second height adjusting member within a second cavity and having a second seat surface for slidable contact along a second contact surface of the second form and wherein the first and second height adjusting members are each adjustable to set the height and angle of the at least first and second sections of the screed within the gap;
- and
- (iv) at least one bucket accepting coupling, wherein the at least one bucket accepting coupling has a slot that extends along the screed in a length direction for accepting a portion of a lip of a bucket for an earth-moving apparatus.
Advantageously, embodiments of the present invention provide a solution for paving installation that is readily scalable for walkways and other structures of various widths and using a wide range of particulate and finished materials.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with reference to the drawings in which:
FIG. 1A is a cross sectional view of a form according to an embodiment of the present invention;
FIG. 1B is a cross sectional view of an alternate form similar to that shown in FIG. 1A;
FIG. 1C is a perspective view that shows joined form sections;
FIG. 2A is a perspective view that shows a connector assembly used to connect forms to a stake;
FIG. 2B depicts a sectional connector used to connect adjacent forms to each other;
FIG. 3A is a perspective view that shows a screed according to an embodiment of the present invention;
FIG. 3B is a perspective view that shows a height selection block;
FIG. 3C is a perspective view that shows a height selection block with a modified seat surface profile;
FIG. 4A shows the screed in a level configuration;
FIG. 4B shows the screed in a convex profile configuration;
FIG. 4C shows the screed in a concave profile configuration;
FIG. 5A shows a front view of a screed for use in applying particulate materials;
FIG. 5B shows a front view of a screed for use in applying paving materials according to an alternate embodiment of the present invention;
FIG. 5C shows an earthmoving bucket inserted into bucket accepting features in a screed; and
FIGS. 6A and 6B provide a flow chart of a process for walkway construction using an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Figures shown and described herein are provided in order to illustrate key principles of operation and fabrication for an apparatus according to various embodiments and a number of these figures are not drawn with intent to show actual size or scale. Some exaggeration may be necessary in order to emphasize basic structural relationships or principles of operation.
In the context of the present disclosure, terms “top” and “bottom” or “above” and “below” are relative and do not indicate any necessary orientation of a component or surface, but are used simply to refer to and distinguish opposite surfaces or different portions of a material. Similarly, terms “horizontal” and “vertical” may be used relative to the figures, to describe the relative orthogonal relationship of components, for example, but do not indicate any required orientation of components with respect to true horizontal and vertical orientation.
Where they are used, the terms “first”, “second”, and so on, do not necessarily denote any ordinal or priority relation, but are used for more clearly distinguishing one element or time interval from another. There are no fixed “first” or “second” elements in what is taught herein; these descriptors are merely used to clearly distinguish one element from another similar element in the context of the present disclosure.
In the context of the present disclosure, the term “paving materials” relates to any of a number of types of finish material, such as bricks or paving tiles, or particulate material that is laid down and formed as part of a base for a tiled or paved surface or wall structure. The paving material may be dry, as in the case of bricks, sand, gravel, or crushed stone, or may be mixed with a liquid, as in the case of concrete, asphalt, or other material. Forming of the material may include various operations used to distribute, shape, condition, or compress the particulate materials, such as spreading, tamping, leveling, rolling, wetting, drying, troweling, and other operations, for example.
In the context of the present disclosure, the term “oblique” describes an angular relationship that is not parallel or normal, that is, other than an integer multiple of 90 degrees. In practice, two surfaces are considered to be oblique with respect to each other if they are offset from parallel or normal by at least about +/−10 degrees or more. Similarly, a line and a plane are considered to be oblique to each other if they are offset from parallel or normal by at least about +/−10 degrees or more.
In the context of the present disclosure, the term “piecewise parallel” has its standard meaning, indicating that two structures may follow the same curved path and extend substantially in parallel at any point along the path. Forms that are on opposite sides of a curved walkway are piecewise parallel when a line that is substantially in parallel with the edge of each form can be extended between the forms.
Embodiments of the present invention address the problem of paving material installation using a combination of a configurable screed and flexible plastic forms that are straightforward to setup, adjust, and use in a particular application. According to an embodiment of the present invention, and shown in FIGS. 1A, 1B, and 1C, forms 100 and 105 are made of reusable and flexible plastic and can be easily manipulated by construction workers to simplify the paving of walkways, sidewalks, patios, pool decks, drive ways, retaining wall footers of all sizes, garden perimeters, concrete walkways, driveways, pads, masonry, and other outdoor structures. While plastic is advantaged for forms 100 and 105, other materials, such as aluminum and composites containing plastics, metals, and binders such as epoxies can be used.
FIG. 1A shows a cross section of form 100 manufactured in a first depth, such as six inches top to bottom, in the vertical view shown. Forms 100 of this depth are typically used for concrete and paving stone projects, for example. FIG. 1B shows a cross section of form 105 manufactured in a 12-inch depth for various types of more permanent structures, such as for retaining wall footers, roadways, and curbing. It will be understood that depth can be varied over a range for different uses. Forms 100 and 105 have integral depth indicators 110 on a front side 120 facing the particulate and paving materials. Depth indicators 110 can be notched, grooved, dimpled, painted, molded, or otherwise marked on front side 120. Depth indicators 110 simplify determining the level of particulate material used as a base, such as to meet layer depths dictated by various standards such as ASTM C 33, Standard Specification for Concrete Aggregates by ASTM (American Society for Testing and Materials) International, West Conshohocken, Pa., for example. Depth indicators 110 can significantly reduce the time and effort needed to measure and provide the desired depth of particulate materials. Depth indicators 110 provide a visual reference that allows workers who are depositing and compacting particulate materials to know at a glance if the desired depth has been reached. A contact surface 108 provides a surface for sliding contact with height selection blocks for the screed, as described in more detail subsequently.
Forms 100 and 105 can be manufactured in preformed lengths, typically 20, 16, 12, 10, or 6 feet long, and can be cut to any length. According to an embodiment of the present invention, forms 100 and 105 are fully pliable, lightweight, and easy to measure and cut. A flange 150, along the base of forms 100 and 105, provides additional strength and a base surface for resting forms 100 and 105 on the ground.
A back side 130 of forms 100 and 105 faces away from the particulate and other paving materials. Back side 130 has channels 140 that allow connection and staking of forms 100 and 105.
FIG. 1C shows a perspective view of back side 130 of a pair of forms 105 that have been connected using a connector 260. It is understood that the perspective view for form 100 is similar. Forms 100 and 105 provide improved flexibility on a longitudinal axis 160 without compromising strength on a vertical axis 170, thus providing the ability to create curved pathways. Even though they are flexible in longitudinal axis 160, forms 100 and 105 also have great strength on vertical axis 170 that resists collapsing or deforming under the weight and pressure of the screed moving on a longitudinal axis 160 across the top of forms 100 or 105 with added weight of a machine such as a Skid Steer Loader S100 from the Bobcat Company, headquartered in West Fargo, N. Dak., or a walk behind skid steer Dingo TX 427 from the Toro Company of Bloomington, Minn.
In FIG. 1C, connector assemblies 200 and sectional connectors 260 have been inserted into channels 140. Forms 100 and 105 can also be positionally adjusted on a horizontal axis 180 by manipulation of connector assemblies 200 as described in more detail subsequently.
FIG. 2A depicts a connector assembly 200 which connects forms 100 and 105 to an anchor 290, shown in top view within a clamp 205. Anchors 290 are typically rebar or some other commonly available staking device. Clamp 205 secures connector 200 to anchor 290. A tightening knob 210 tightens clamp 205 on anchor 290 and also tightens a barrel clamp 207 onto a clamp tube 225. A rotary T-slot bolt 215 extends through a washer 220 and clamp tube 225 and also through a wing nut 230 to terminate at a handle 235. Rotary T-slot bolt 215 is threaded such that handle 235 can be affixed with a nut 236, and also so that wingnut 230 can be rotated to adjust pressure on washer 220 via clamp tube 225. Various washers and nuts can be added to connector assembly 200 to facilitate its function.
In practice, connector assembly 200 secures forms 100 and 105 to anchors 290. For the purpose of example and not by way of limitation, a preferred method of securing form 100 in place is described. Clamp 205 is first set loosely on anchor 290. Anchor 290 is then pounded into the earth such that it is solidly secured and has minimal opportunity to move but still accessible to connector assembly 200. Rotary T-slot bolt 215 is inserted into channel 140 and handle 235 is rotated so that head 217 of rotary T-slot bolt 215 is captured inside channel 140. Wing nut 230 is rotated to pinch channel 140 between head 217 of rotary T-slot bold 215 and washer 220, securing connector assembly 200 to form 100. When form 100 is set in the desired position, tightening knob 210 is rotated, which tightens clamp 205, fixing the vertical position of form 100. Tightening knob 210 also fixes barrel clamp 207 to clamp tube 225, fixing position of form 100 or 105 on horizontal axis 180. Prior to rotating tightening knob 210, barrel clamp 207 can slide on clamp tube 225 so that the horizontal position of form 100 can be adjusted relative to the position of anchor 290.
The positional flexibility of connector assembly 200 provides substantial time savings over prior art connectors. Connector assembly 200 is easily adjusted in all three axes relative to forms 100 and 105. Because head 217 of rotary T-slot bolt 215 can be inserted and secured anywhere along channel 140, connector assembly 200 can move freely along longitudinal axis 160 toward the position of anchor 290. Clamp 205 can be set anywhere along the height of anchor 290, simplifying vertical adjustment of form 100 or 105. Advantageously, anchor 290 can be driven at an angle other than vertical, and clamp 205 will rotate on clamp tube 225 to accommodate the nonvertical angle of anchor 290. This can happen, for example, where the paving site has rocks or other impediments. Barrel clamp 207 is free to slide along a portion of the length of clamp tube 225, so that adjusting the distance along horizontal axis 180 between opposite forms 100 or 105 is facilitated. The positional flexibility of connector assemblies 200 provides time and labor savings by eliminating tedious resetting of anchors 290 for stabilizing the forms.
FIG. 2B shows section connector 260, which is used to connect sections of forms 100 or forms 105 to each other. A link base 265 supports and is connected to link studs 270. Washers 275 are centered on link studs 270. Washers 275 can be a single washer or multiple washers, one of which can be an internal tooth lock washer. Terminations of link studs 270 are threaded. Four-arm knobs 280 are coupled to link studs 270. To connect a plurality of forms 100 or a plurality of forms 105 together, section connector 260 is inserted into channels 140 on adjacent forms. Link base 265 is configured to fit easily into channels 140 at the longitudinal ends of forms 100 or 105. Once connector 260 is in place in channels 140 and with adjacent forms butting up to each other, four-armed knobs 280 are tightened, pinching channels 140 between link base 265 and washers 275. Connected by section connector 260, adjacent sections of forms 100 or 150 are held in place such that they can be handled and positioned as one continuous form.
FIG. 3A shows a screed 300 of the invention. Screed 300 is a leveling device. However, unlike screeds commonly used in the industry, screed 300 is reusable, is easy to assemble, and is adjustable such that it assists in saving labor while accurately leveling base and sub base particulate materials at different levels for proper support of finished paving materials such as paving blocks, bricks and concrete. A screed body 305 is substantially rectangular, can be made of metal such as steel or aluminum, or fiberglass or other composite material, and is formed of two or more coupled sections, shown in FIG. 3A as sections 310, 320, 322, and 330. Note that various other materials, such as plastic may be used, or a composite of metal and plastic or of different metals may be used to construct screed 300. FIG. 3B shows one of the height selection blocks 355 used for height adjustment at each end of screed 300. Each height selection block 355 has a seat surface 358 that slides along the top of forms 100 or 105 and has holes 370 for height adjustment. FIG. 3C is a perspective view that shows a height selection block with a modified seat surface profile along seat surface 358. Slidable contact between height selection blocks 355 and contact surface 108 on forms 100 or 105 provides a reduced-friction interface that allows the assembled screed 300 to be dragged or pushed along the trench in order to distribute particulate or finished paving materials at the desired height. Height selection block 355 can be a plastic or metallic material, or a reduced-friction composite material, for example.
Referring to FIG. 3A, screw handles 340 affix clamps 345 to screed body 305 and affix sections 310, 320, 322, and 330 together to create a strong and complete screed body 305 from modular components. Clamps 345 have bucket accepting couplings 347, each with a slot 348 for rapid and easy insertion of the lip of a bucket or blade of earthmoving machinery such as a Skid Steer Loader S100. Slot 348 extends in the length direction (longitudinal axis) of the screed 300. By means of bucket accepting features 347, commonly available excavating buckets on earthmoving apparatus can be used to quickly couple screed 300 to earthmoving equipment and facilitate machine powered use of screed 300, with further savings of time and labor. The position of the at least one bucket accepting coupling along the length direction of the screed is adjustable. Slot 348 may be of fixed width, that is, fixed jaw size, or may provide adjustable jaw size, such as using a clamp.
Outside ends 335 of sections 310 and 330, away from central section 320, have wings or projections 342. Projections 342 extend beyond screed body 305 and terminate in an open vertical channel 350 that provides a cavity with a square opening in the embodiment shown. Height selection block 355 fits into open vertical channel 350, and is fixed in position within the cavity provided by open vertical channel 350 by a bolt 360 which passes through holes 365 in open vertical channel 360 and also passes through one of holes 370 in height selection block 355, shown in FIGS. 3B and 3C. According to an alternate embodiment of the present invention, a clamp is used to adjust and hold height selection block 355 in position within vertical channel 360.
Note that seat surface 358 as shown in FIGS. 3A and 3B can be flat or can have a curved profile designed to facilitate slideable contact along the top contact surface of the forms. The profile shown in FIG. 3B is provided by way of example and not by way of limitation. The plurality of holes 370 in height selection block 355 allows for easy selection of different descent depths for screed body 305. Depth indicators 110 on the forms (FIGS. 1A and 1B) can be used to help determine the height setting of height selection blocks 355 of screed 300.
Still referring to FIG. 3A, bolt 360 is secured in place by a nut or other fastener (not shown). Note that projections 342, while designed to ride atop forms 100 and 105, do not extend far beyond the forms. This allows anchors 290 secured by connector assemblies 200 to forms 100 and 105 to be driven into the ground without interference with screed 300. Connector assemblies 200 are designed so that the portion which passes under the projections and height selection blocks 355 does not interfere with the operation of screed 300.
FIGS. 4A, 4B and 4C show different arrangements of central sections 320 and 322 of screed 300 that can be used depending upon curvature changes, such as changes needed due to drainage differences or aesthetic preferences for a specific project. FIG. 4A shows central sections 320 and 322 leveled, for use when a level top surface for particulate matter is desired. A bottom surface 312 of screed 300 lies completely flat, with a flat profile so that screed 300 can shape particulate material between forms 100 or 105 to be level or to follow the contour of the ground.
In places where a flat profile would be undesirable, such as a walkway between buildings, the arrangement of FIG. 4B would be used. Here, central sections 320 and 322 provide a bottom surface 314 that has a convex curvature profile. This imparts a concave top surface to particulate matter that is deposited between forms 100 or 105. Alternately, the arrangement of FIG. 4C shows a bottom surface 316 that has a concave curvature profile. This imparts a convex top surface to particulate matter that is deposited between forms 100 or 105. The bottom surface profile that is used can be determined by the preformed shape of sections 320 and 322 or can be determined by how these sections are coupled together, allowing the same components to provide a flat, convex, or concave surface profile for particulate material or finished paving material. It will be understood that any number of angles can be supported by central sections manufactured with different angles or coupled at different angles (not shown). Additionally, central sections of screed 300 are not limited to a single point of discontinuity and can also be curved. Also, sections 310, 320, 322, and 330 can be constructed in different lengths to enable a longer or shorter screed, or additional sections can be removed for a shorter screed length or added for a longer screed length according to the needs of a particular site.
Screed sections 320 and 322 have tongue protrusions 325 at one end and sleeve openings 327 at the opposite end as fittings for joining to additional sections. Protrusions 325 are configured to fit into openings 327 for each section, to provide a coupling arrangement that is similar to a mortise and tenon joint familiar to woodworkers. Note that screed 300 may also be manufactured with expanding sections that slide over each other, bolt or fasten together in some way, or in some other combination that allows coupling of screed sections together to allow variable screed length and curvature profile.
In operation for forming a supporting base, screed 300 is dragged across each layer of particulate material that is spread between the forms, producing a uniform, compact layer. Screed 300 can be dragged by hand for smaller projects. For larger projects, screed 300 can be moved along with a bucket attachment that creates compressive downward force; this type of operation can use a walk-behind device such as a skid steer Dingo TX 427 Wide Track from Toro Corporation, Bloomington, Minn., or use operator-driven machinery such as a Skid Steer Loader S100 from Bobcat Co., division of Doosan Infracore International, Seoul, South Korea. Multiple passes with screed 300 can be employed for a particular layer since compacting and addition of additional particulate material can be necessary for achieving a base with the proper characteristics for supporting the finished layer.
Some installations, for example, require a two-inch base for concrete projects. FIGS. 5A and 5B are side views taken between forms 100 and 105, respectively, that shows forms 100 and 105 in place on ground 500 with screed 300 in contact with forms 100 and 105 and configured for movement along piecewise parallel forms 100 and 105. In order to conform to standard practice, two inches of a base 510, such as gravel in this case, must be placed against ground 500 and within a gap 502 prior to overcoating with three inches of concrete to be poured above base 510.
In FIG. 5A, screed 300 is shown leveling base 510. As described previously, height selection blocks 355 are fitted into open vertical channels 350, and are fixed in open vertical channels 350 by bolts 360 which have been inserted through holes 365 in open vertical channels 360 and through the hole 370 in height selection blocks 355. With this arrangement, screed 300 is leveled by contact with form 100 along contact surface 108, causing screed 300, in turn, to level and compact base 510 at the desired height. Note that the depth to which screed body 305 descends between forms 100 matches depth indicators 110 on forms 100, which provides a simple checking mechanism to verify that particulate material has been leveled at the correct height. Time consuming raking and re-leveling, which can be needed when particulate material is found to be deposited in an uneven or elevated manner, is eliminated by the accurate depth adjustment of screed 300 by height selection blocks 355. Also note that if a level of particulate material is desired that does not match the level of opposing forms 100 or 105, height selection blocks can be set to select different heights for each side of screed 300, and the angle of the particulate material between forms 100 or 105 can be modified.
Paving stone projects often require two base layers, as shown in FIG. 5B. In this cross sectional view, screed 300 has been employed in contact with forms 105 in the manner shown in FIG. 5A, but with two different positions for height selection blocks 355. A four-inch sub base 550, such as gravel, supports a one-inch fluff layer 560, such as sand, which in turn supports a finished layer of paving stones (not shown). Other finished surface materials such as flagstone or bricks can also be used.
FIG. 5C shows a lip 576 of a bucket 575 inserted into bucket-accepting features 347 secured in clamps 345 of screed 300. As shown, screw handles 340 are used to clamp sections of screed 300 to form one solid unit. Bucket 575, attached to some kind of earthmoving apparatus such as a Skid Steer Loader S100, is inserted into screed 300 by moving lip 576 of bucket 575 into slot 348 of bucket accepting features 347 or alternatively by manually moving screed 300 toward bucket 575 so that bucket accepting features 347 accept lip 576 of bucket 575. Note that one or more additional clamps 349 may optionally be provided with clamp 345 to affix bucket accepting features 347 of screed 300 to bucket 575, as shown in outline in FIG. 5A. Once screed 300 is coupled to bucket 575, the earthmoving apparatus operator places the screed 300 atop forms 100 or 105 and pulls or pushes particulate material between forms 100 or 105 to the appropriate depth as dictated by the settings of height selection blocks 355, applying compressive pressure so that the screed maintains its position atop forms 100 or 105 while spreading the particulate material at the proper depth.
Steps for installation of a paving stone walkway using an embodiment of the present invention are given in the flow chart shown in FIGS. 6A and 6B. It will be understood that this description is employed by way of illustrative example only and not by way of limitation.
Referring to FIG. 6A, excavations are made only inches wider than the desired finished surface in an excavation step 600. In a bolt insertion step 605, rotary T-slot bolts 215 of connector assemblies 200 are inserted into the channels 140 on the back side of forms 105. Anchors 290 are inserted through clamp 205 in connector assembly 200 in an anchor installation step 610, loosely joining form 105 to anchor 290. Each anchor 290 is pounded into the ground to create a secure point of connection to the earth. When the anchor 290 can't be pounded in, due to obstruction by a rock or other object, the connector assembly 200 is moved along the channel, allowing anchor 290 to move without affecting the position of form 105 in either a vertical or horizontal direction. Note that, in addition to being able to be moved laterally, the connector assemblies 200 can be set to accept anchor 290 pounded into the earth at any angle. This allows setting form 105 in place with enough strength to withstand the pressure of the particulate material placed between forms 105 even in the event of a rock blocking the preferred position for anchor 290.
Continuing with the FIG. 6A sequence, after anchors 290 are pounded into place, four arm knob 230 and tightening knob 210 are tightened, anchoring form 105 to the earth in a securing step 620. Another advantage of embodiments of the present invention is that additional anchors 290 and connector assemblies 200 can be added at any previously unoccupied point along channels 140 at any time. Should it become apparent that stronger anchoring is necessary during the process of preparing sub base 550 or fluff layer 560, additional anchors 290 and connector assemblies 200 can be added at any point necessary without the need for disassembling previously assembled anchors 290 and connector assemblies 200.
When one form 105 is secured in place, then the complementary, piecewise-parallel form 105 along the opposite edge of the walkway is anchored by the same method. Note that the position of form 105 can be easily adjusted to the specifications of the job because connector assemblies 200 are readily adjustable in a leveling step 625. For example, if the forms 105 on either side of the walkway are to be level with one another, the relative heights of the forms can be quickly adjusted to level by loosening tightening knob 210, adjusting the height of form 105, and then re-tightening tightening knob 210. Note that screed 300 can be placed between forms 105 to assist in making sure that the distance between forms 105 is proper. When the walkway or other structure is straight, the task of adjusting connector assemblies 200 so that opposing forms 105 are parallel is straightforward. When the walkway to be created is curved, adjusting connector assemblies 200 so that opposing forms 105 are piecewise parallel is facilitated.
In a connector insertion step 630, section connectors 260 are inserted into channels 140 of the form 105 that has been secured to the earth, and to each additional form 105 that is moved into an adjacent position. Additional adjacent form 105 butts up against form 105 which is already secured to the earth. Note that butting the ends of forms 105 to each other and connecting the forms 105 by tightening four armed knobs 280 in a connection step 635 assists in positioning additional adjacent form 105 when the previously described process for securing forms 105 to the earth is repeated. As forms 105 are added, additional adjacent forms 105 tend to follow the same line that is established by the top or bottom of the initially installed form 105. In this way, the tedious task of leveling or contour filling is minimized. In common practice, a string line or laser is used to establish the top position of forms 105. In contrast to using wood or metal forms, the easy vertical positioning of forms 105 provides a simplified mechanism that can readily match a string line or laser leveling device. Also, use of forms 105 prevents the need for large numbers of anchors, as is necessary for use with wood forms due to warping, bowing and twisting.
Continuing with the sequence in FIG. 6A, when the desired number of forms 105 have been installed, ground 500 is leveled. This can be done with at least one pass of screed 300 in a leveling step 640. In a dumping step 642, particulate material such as gravel or sand is placed between forms 105. In a preferred embodiment, sub-base 550, in this case gravel, is first placed between the forms. Unlike practices of the prior art, where multiple small piles of gravel are placed between prior art forms for tedious raking operations, larger piles of gravel can be deposited at one time between the forms. Screed 300 is used to push or pull sub base 550 to the desired level in a leveling step 645. Projections 342 on each end of screed 300 fit over the top of forms 105 and restrict the descent of screed body 305 into the space between forms 105. The depth of descent of screed body 305 is controlled by the selection of hole 370 through which bolt 360 is inserted in height selection block 355. The bottom of height selection block 355 provides seat surface 358 upon which screed 300 can ride atop contact surface 108 of forms 100 or 105. Sub-base 550 is compacted in a compacting step 647 with a plate compactor such as the BPU 2540A Reversible Vibratory Plates provided by the Wacker Neuson Company of Munich, Germany. Note that steps 642, 645 and 647 can be carried out a number of times until the desired height and compaction of sub-base 550 is achieved, as determined in a verification step 649. After sub base 550 has been installed, the depth of descent of screed body 305 is reduced by selecting the appropriate hole 370 through which bolt 360 is inserted in height selection block 355 in a screed adjustment step 650.
FIG. 6B shows additional steps in the process. Fluff layer 560, in this case sand, is deposited atop sub base 550 in a dumping and leveling step 655. As with step 640, large piles of sand can be deposited between forms 105. In step 655, screed 300 is used to push or pull fluff layer 560 to the desired level. Fluff layer 560 is compacted in a compacting step 660 with a plate compactor or other suitable device. Note that steps 655 and 660 can be performed a number of times until the desired height and compaction of sub-fluff layer 560 is achieved, as checked in a verification step 664. In a stone installation step 665, paving stones are installed on top of the base prepared by this process.
A disassembly step 670 then follows, in which the forms structure is systematically removed. Connector assemblies 200 are loosened by rotating two armed knob 210, four armed knob 230 and two armed knob 235, and then removed, disconnecting forms 105 from anchors 290. Forms 105 are removed from the ground. Sectional connectors 260 are removed. Anchors 290 are then removed. Backfilling the area of overdigging occurs in a backfill step 690 and the installation is complete.
Screed 300 can be moved along the length of contact surface 108 of forms 100 or 105 by hand. Alternately, screed 300 can be moved using machinery, which is advantageous where the width between forms 100 or 105 is large, for example, when this width is 4 feet or more. Because some projects dictate that screed 300 be moved by machinery, clamps 345 of screed 300 have bucket accepting features 347 for insertion of a bucket for equipment often used in construction. Once the lip of the bucket is inserted into slot 348 of bucket accepting features 347, the front-loader or other piece of mobile earthmoving apparatus drags the screed along the top of the forms 100 or 105 to achieve the desired profile for deposited particulate material. Note that the length of screed 300 can be adjusted by using sections of different length dimensions, or by adding additional sections. In practice, embodiments of the present invention are particularly well suited for use for widths between 15 inches and 20 feet; however, embodiments of the present invention are not limited to those dimensions.
Use of forms 100 or 105, connector assemblies 200, section connectors 260 and screed 300 reduces the time necessary for preparation of layers supporting the finished materials, and in the case of concrete, can reduce the time required for installing that finished material. Due to the accurate leveling of large amounts of material that is placed between the forms 100 or 105, tedious and error-prone hand raking can be greatly reduced or eliminated. Also, placing material by hand with multiple wheelbarrow loads may no longer be necessary. Construction crews can substantially cut the cost and time of paving projects because the forms 100 or 105, connector assemblies 200, section connectors 260 and screed 300 are reusable, light weight, and easy to configure and manipulate. Thus, crews using the described solution can produce a superior product that meets or exceeds industry standards with reduced time and labor. Screed 300 can be used by hand or with any of a number of types of earth-moving apparatus and related equipment that have a blade or bucket, including systems that seat an operator and walk-behind systems, for example.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention as described above, and as noted in the appended claims, by a person of ordinary skill in the art without departing from the scope of the invention. The invention is defined by the claims.
Patent Application
20160281302
