Double-bladed vibrating concrete screed

Abstract

A concrete screed includes an engaging frame for readily engaging the mounting fixture of a skid loader or the like, with a pair of spaced parallel frame arms long enough to keep the skid loader off the concrete form, with a screed blade attached to the distal ends of the two frame arms. A pre-screed screeding blade having a V-shape is fixed to the screed blade for knocking down high spots in poured concrete. The side frame arms are free to pivot up and down at both ends. A pair of pulling arms, each pivotally connected to the screed blade at one end and to a side frame arm at the other, exert the actual pulling force that pulls the screed blade across the poured concrete. A pair of hydraulic vibrators fixed to the screed blade vibrates the screed blade to puddle and settle the concrete for leveling.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

SEQUENCE LISTING

Not applicable

BACKGROUND OF THE INVENTION

The present invention is related to an apparatus for leveling concrete. More particularly, the present invention is directed to leveling concrete in an area between two forms for retaining poured concrete.

DESCRIPTION OF THE RELATED ART INCLUDING INFORMATION DISCLOSED UNDER 37 C.F.R. 1.97 and 1.98.

The present invention is a double-bladed vibrating concrete screed for leveling poured concrete within a form, such as a driveway. Concrete is often poured from a chute at the back of a concrete truck or through a hose or nozzle. Although the chute or hose can be moved about to some extent, the concrete is invariably not level when poured and must be subsequently leveled before setting. In many applications, the leveling is carried out by a hand tool known as a screed that a worker drags across the concrete. The present invention is designed to reduce the labor needed for this operation by providing a screed that can be attached to a front loader, excavator, or the like which can control the elevation of the screed and drag it back and forth across the concrete, thereby leveling the concrete more quickly and easily.

The requirement for leveling poured concrete has prompted the development of many different techniques and inventions, some of which have been patented. Some of these are discussed below.

U.S. Pat. No. 7,121,762 B2, issued to Quenzi et al. on Oct. 17, 2006, discloses an Apparatus for Screening Uncured Concrete Surfaces, comprising a screeding device having a primary screed member, or vibratory beam that is mounted to a framework. The device includes a strike-off plow, which strikes the concrete before the vibratory beam. This device is pulled by a user as he walks backward

U.S. Patent Application Publication Number US 2005/0265786 A1, describing an invention by Gresser et al. and published on Dec. 1, 2005, discloses a Method and Apparatus for Leveling Spreadable Material, comprising a screed member supported by a pair of parallel rails that are rigidly is attached to the bucket of a front loader through a pair of receiving sleeves attached to the bucket. The actual screed is supported by a pair of ski-like skids that rest on the ground or other substrate that must be moved through the material being graded. Although the screed arms have some up-and-down adjustment relative to the skids, there appears to be none where the arms are attached to the bucket of a front loader.

U.S. Pat. No. 6,203,244 B1, issued to Van Ornum on Mar. 20, 2001, discloses a Screeding Apparatus, comprising a screed blade connected to a rear edge of a square frame that is supported by casters near the end opposite from the screed blade and having a fitting along the rear edge for receiving the prongs of a front loader or the like, which pulls the screed blade across concrete or the like. Since the casters ride on the ground, the screed will cause the material that is spread to have a surface contour related to the contour of the ground.

U.S. Pat. No. 6,022,171 B1, issued to Munoz on Feb. 8, 2000, discloses an Apparatus and Method for Preparing a Site and Finishing Poured Concrete, comprising a concrete finishing device 24 attached to the front of a motorized vehicle 20 (FIG. 1). The concrete finishing device includes first and second vibrating floats. A screed plate comprises a first screed plate in the concrete finishing device, which comprises a second screed blade located and attached forward of the vibrating floats and they will push the material during fine grading.

U.S. Pat. No. 5,567,075 B1, issued to Allen on Oct. 22, 1996, discloses an Offset Screed System and Quick Connect Mounting Therefore, comprising a triangular truss frame 40 with a leading strike-off member for scraping off excess concrete followed by an identically shaped float, both of which are formed from angle iron or the like, with the leading strike-off member leading with its horizontal edge, while the float member leads with its vertical face. Vibrators are used to vibrate discrete and may be driven by a conventional motor driving the eccentrically weighted shaft 45 or by pneumatic or electric vibrators (column 6, lines 13-23).

U.S. Pat. No. 5,273,375 B1 issued to Plourde on Dec. 28, 1993, discloses a Trench Paving Device, comprising a screed for attaching directly to the lower lip of a front loader bucket by clamps. The device comprises a pair of opposed vertically oriented and rearwardly converging side plates disposed between the two side plates lies a vertically disposed rectangular plate which serves as the screed.

U.S. Pat. No. 5,129,803 B1, issued to Normura et al. on Jul. 14, 1992, discloses a Concrete Leveling Machine, comprising a motor vehicle having a drive system that pulls a leveling unit. The wheels of the motor vehicle are designed to ride on the reenforcing bar for the concrete. The leveling unit includes an elongated leveling augur, a leveling plate and a tamper. The tamper is supported by two tamper support rods attached to the level of platform. The support rod is forced down with a coil compression spring. A tamper motor causes the tamper to shake up and down. The screed, is illustrated as being convex from bottom to top in the direction of travel and being physically higher than the tamper, although this appears not to be discussed in the verbal specification.

U.S. Pat. No. 5,039,249 B1, issued to Hansen et al. on Aug. 13, 1991, discloses an Apparatus for Screening (sic; it should read Screeding) and Trowelling Concrete, comprising telescopic boom attached to a motor vehicle located away from the poured concrete. A screed attachment includes screed blade and a concrete float that is connected to a support member that is connected to two lifting rods. This entire assembly is connected to the boom. The screed blade is convex from top to bottom relative to the direction of travel, that is, is shaped like a short snow plow blade

U.S. Pat. No. 4,995,760 B1, issued to Probst et al. on Feb. 26, 1991, discloses a Scraping Device for Making a Subgrade, comprising a scraper blade connected to a bucket for accumulating grade material, for example, sand, as they scraper is dragged across a pair of parallel rails set at the desired grade level.

U.S. Pat. No. 4,685,826 B1, issued to Allen on Aug. 11, 1987, discloses a Vibratory Screed Including a Laterally Displaceable Oscillating Strike-Off, comprising a self-contained hydraulic system for vibrating a strike-off attachment (FIG. 16) of a vibratory screed. The apparatus includes front and rear screed blades, both of which are flat, making them actually floats rather than screeds. This device is vibrated by the gasoline engine apparatus mounted on top of the apparatus.

U.S. Pat. No. 3,786,997 B1, issued to Viner on Jan. 22, 1974 discloses an Apparatus for Removing Unused Concrete, that is used for reclaiming ready-mix concrete that is left over after a job. The excess concrete is poured into a shallow form, allow to set and is then crushed by advancing a curved blade on a front end loader. The resulting debris can be used as aggregate and additional concrete.

U.S. Pat. No. 2,734,433 B1, issued to Brown on Feb. 14, 1956, discloses a Trowel Device comprising a screed or trowel laid across uncured pavement material. The trowel is connected to a platform 22 where an operator stands and rocks an activation lever back and forth, thereby causing the trowel to slide back and forth and to smooth the pavement surface.

The references described above do not disclose or suggest a concrete screed having the utility or versatility of the present invention, which can be, in the embodiment discussed below, that can be entirely used by a single operator, including assembly, disassembly, use, and transporting.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is a primary object of the present invention to provide a double-bladed vibrating concrete screed that levels concrete more effectively by allowing the screed blade to pivot up and down.

It is another object of the present invention to provide a double-bladed vibrating concrete screed that has two screeding blades with a smaller first screeding blade, or pre-screeding screed blade for knocking down high spots in poured concrete so that the primary screed blade, or screed blade, is not overtopped by poured concrete, enabling most concrete to be sufficiently leveled in a single pass.

It is another object of the present invention to provide a double-bladed vibrating concrete screed that can be readily assembled and disassembled into easily transportable sections.

It is another object of the present invention to provide a double-bladed vibrating concrete screed that isolates up and down movement of the frame arms at either end of the frame arms from corresponding movement by the screed blade.

These and other objects of the present invention are achieved by providing a pair of parallel frame arms that can be attached to a skid loader or the like to pull the screed blade attached to the distant end of the frame side arms. The screed blade is perpendicular to the frame side arms and is designed to overhang the concrete forms, as riding along the tops of the concrete forms allows the screed blade to level and smooth poured concrete at the level of the tops of the concrete forms. Hydraulic vibrators vibrate the screed blade to puddle and smooth the poured concrete as the screed blade is drawn across it. Attached to the front face of the screed blade is a V-shaped pre-screed screeding blade for knocking down high spots or piles in the poured concrete before the primary screed blade passes over the concrete. The pre-screed screeding blade helps prevent the poured concrete from piling up against and overtopping the screed blade, which would require making a second pass over the poured concrete or would require additional manual working of the concrete.

The primary screed blade is connected to the distal ends of the frame side arms by a mechanism that allows the screed blade to vibrate up and down. In order to pull the screed blade from approximately its lower edge, the concrete screed includes a pair of pulling arms that actually transmit the force to pull the screed blade, while the point of attachment of the frame side arms to the screed blade have very little, or no, pulling force exerted on them. The pulling arms are pivotally connected to the screed blade at one of their ends and are pivotally connected to the frame side arms at a point along the arms.

Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, the preferred embodiment of the present invention and the best mode currently known to the inventor for carrying out his invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a rear perspective view of a double-bladed vibrating concrete screed according to the present invention showing the double-bladed vibrating concrete screed attached to a skid loader and being used to level poured concrete within a form.

FIG. 2 is a front perspective view of the double-bladed vibrating concrete screed of FIG. 1.

FIG. 3 is rear perspective view of the double-bladed vibrating concrete screed of FIG. 1 shown in use leveling poured concrete within a form.

FIG. 4 is a rear perspective view of the attachment bracket of the double-bladed vibrating concrete screed of FIG. 1, which is located at one end of the double-bladed vibrating concrete screed, which is attached to the skid loader.

FIG. 5 is a front perspective view of the attachment bracket of FIG. 4.

FIG. 6 is an enlarged fragmentary rear perspective view of the attachment point of the attachment bracket of FIG. 4.

FIG. 7 is a rear view of the screed blade of the double-bladed vibrating concrete screed of FIG. 1 showing the adjustable slot mechanism for allowing the screed blade to be adjusted from straight to an arc to provide a crown in the poured concrete.

FIG. 8 is a rear perspective view of a spring mounting mechanism of the screed blade on the double-bladed vibrating concrete screed of FIG. 1 that allows the screed blade to vibrate up and down, with the hydraulic vibrator omitted for clarity.

FIG. 9 is an enlarged fragmentary rear top perspective view of a portion of the screed blade of the double-bladed vibrating concrete screed of FIG. 1 showing an enlarged view of one of the two hydraulic vibrators that are fixed to the screed blade, with the side arm of the frame omitted for clarity.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a double-bladed vibrating concrete screed (concrete screed) 10 is pivotally connected to a skid loader 12, or the like, utilizing the attachment fixtures of the skid loader 12, which pulls the concrete screed 10 forward in the direction of the arrows 14 to pull the primary screed blade, or screed blade 16 along the poured concrete 18 to level and smooth the poured concrete surface 20, assisted by the two spaced hydraulic vibrators 22, which are conventional and are actuated by circulating hydraulic fluid pressurized by a conventional hydraulic pump delivering and recovering hydraulic fluid through the hydraulic hoses 23. The hydraulic vibrators 22 are preferably hydraulic motors that rotate a weight off-set from the drive shafts of the hydraulic motors, which rotate at about 800 rpm, providing a stronger and slower vibration than an actual conventional hydraulic vibrator, spreading the poured concrete 18 more effectively. The poured concrete 18 is retained within the space defined by a left-hand side concrete form 24 and a right-hand side concrete form 26, which are conventional, typically dimensional lumber held in place by stakes. In many applications, the left-hand side concrete form 24 and the right-hand side concrete form 26 are straight and parallel, as shown in FIG. 1, but other shapes can be employed. In many cases, there will also be another concrete retaining form at either or both ends of a completed form. In any case, a portion of the screed blade 16 at or along the left-hand end 28 of the screed blade 16 must rest on the top edge 30 of the left-hand side form concrete 24 and a portion of the screed blade 16 at or along the right-hand end 32 of the screed blade 16 must rest on the top edge 34 of the right-hand side concrete form 26. The top edges 30, 34 of the concrete forms 24, 26 serve as guides to forming the top surface of the finished concrete. Left and right are defined with respect to the view of an operator in the skid loader 12, who will be looking toward the concrete screed 10 and driving backward.

Still referring to FIG. 1, the screed blade 16 is formed from a length of metal angle iron having a front face or plow portion consisting of a vertical face 36 and a horizontal portion or face 38, that strengthens the screed blade 16 and presents a smoothing lower surface to the poured concrete 18 for better distribution and smoothing of the poured concrete 18. The screed blade 16 can be made from steel, but is preferably made from a strong aluminum alloy to reduce weight. A pre-screed screeding blade 40 is fixed to the screed blade 16 and presents itself to the poured concrete 18 in front of the screed blade 16. The purpose of the pre-screed screeding blade 40 is to help level and disburse the poured concrete 18, which typically is not poured level, but rather tends to have one or more piles that are significantly above the desired finished grade. Without the pre-screed screeding blade 40, frequently concrete would ride up and over the screed blade 16 as long as it was of any reasonable height, resulting in concrete behind the screed blade 16 that was neither smooth nor level. It is desirable that the screed blade 16 make only a single pass over the poured concrete to save time and to prevent surface voids and to allow the cement to flow over the aggregate to provide an aggregate-free surface for final finishing. The pre-screed screeding blade 40 includes a left-hand side member 42 and a right-hand side member 44 fixed together by welding or the like to present a forward-projecting nose portion 46, forming a V-shape in the pre-screed screeding blade 40. The left-hand side member 42 of the pre-screeding screed blade 40, formed of right-angle material, includes a vertical face 43 and a horizontal face 45. The right-hand side member 44 of the pre-screed screeding blade 40, formed of right-angle material, includes a vertical face 47 and a horizontal face 49. The vertical faces 43, 47 are presented to the poured concrete prior to screeding, that is, they face forward. Other shapes of a pre-screed screeding blade 40 have been tried, including an arcuate shape and these other shapes may be used. The height and dimensions of the pre-screed screeding blade 40 are different from the screed blade 16, as discussed below in connection with FIGS. 2, 3.

Still referring to FIG. 1, the screed blade 16 is connected to the skid loader 12 by a pair of elongated spaced apart parallel frame arms, including a left-hand side frame arm 48 and a right-hand side frame arm 50. The frame arms 48, 50 are designed to be long enough that the screed blade 16 can be drawn across the expanse of poured concrete 18 in a single pass without having the skid loader 12 drive across either the poured concrete 18 or the concrete form into which the concrete is to be poured, which could damage the form. The distal end 52 of the left-hand side arm 48 is connected to the left-hand side mounting bracket 54 that is fixed to the screed blade 16 and the distal end 56 of the right-hand side arm 50 is connected to a right-hand side mounting bracket 58 that is fixed to the screed blade 16. The mounting brackets 54, 58 allow the screed blade 16 to move up and down, within limits, without any corresponding up or down movement by the arms 48, 50 (See particularly FIG. 8, below). The proximal end 60 of the left-hand side arm 48 is connected to a left-hand mounting pocket 62 in the proximal frame member 64 by the pin 66, while the proximal end 68 of the right-hand side arm 50 is connected to a right-hand mounting pocket 70 by the pin 72. The pins 66, 72 allow the arms 48, 50 to pivot up and down without regard to any up or down movement of the skid loader 12 or the proximal end frame member 64, thereby allowing the screed blade 16 to ride along the tops 30, 34 of the concrete form members 24, 26 regardless of any differences in the terrain or grade of the ground that the skid loader 12 is traveling along. Fittings along the back side of the proximal frame member 64 allow it to be dropped securely onto the attachment plates of the skid loader 12 (see FIGS. 2, 5, below).

Referring to FIG. 2, the horizontal faces 45, 49 of the pre-screed screeding blade 40 are in the same plane and at the same level as the horizontal face 38 of the screed blade 16. The pre-screed screeding blade 40 has a V-shape with a leading edge or nose 46 in the middle of the longest dimension, i.e., the width, of the pre-screed screeding screed blade 40, which forms an angle between the two members 42, 44 lying in the range of 110°-150°, with the preferred angle being 135° from the leading edge or nose 46 toward the rear of the concrete screed 10. A top edge 74 of the pre-screed screeding blade 40 is somewhat lower than a top edge 76 of the screed blade 16. A left-hand end 78 of the pre-screed screeding blade 40 terminates well inside the left-hand end 28 of the screed blade 16 and is fastened to it. A right-hand end 80 of the pre-screed screeding blade 40 terminates well inside the right-hand end 32 of the screed blade 16 and is fastened to it. The pre-screed screeding blade 40 is forward-projecting V-shaped and is shorter than the screed blade 16 in order to perform a preliminary and partial spreading and smoothing of the poured concrete 18 sufficiently that the screed blade 16 can finish the poured concrete 18 and to prevent the poured concrete 18 from piling up and on the screed blade 16 and pouring over its top edge. A horizontal triangular gusset 84 reinforces the connection between the back end 86 of the right-hand side member 44 of the pre-screeding blade 40 and the screed blade 16 toward its right-hand end 32 and a horizontal triangular gusset 88 reinforces the connection between the back of the left-hand side member 42 of the pre-screed screeding blade 40 and the screed blade 16 toward its right-hand end 32. A pair of spaced parallel reenforcement angle-iron type aluminum struts 92 are fixed to the pre-screed screeding blade 40 at one end and to the screed blade 16 at the other, in the space between the two screed blades 40, 16. An adjustment mechanism 94 includes a vertical slot 95 in the middle of the vertical face 36 of the screed blade 16 to permit forming concrete with a crown if desired (see FIG. 7).

Still referring to FIG. 2, the proximal frame member 64 includes a lower horizontal frame member 96 and a parallel upper horizontal frame member 98 that are connected by a left-hand vertical member 100 and a spaced parallel right-hand frame member 102, which are symmetrically offset from the middle of the length of the proximal frame member 64. A right-hand end vertical member 104 and a parallel left-hand end vertical member 106 complete a planar box-type portion of the proximal frame member 64. A right-hand side gusset plate and arm boot 108 secures the pin 68 and the arm 50, while a corresponding left-hand side gusset plate and arm boot 110 secures the pin 66 and the arm 48 (with these gusset plate and arms 108, 110 being shown more fully in FIGS. 4, 5, 6). An upstanding right-hand side interior gusset plate 112 includes an inward bend 114, forming an inward leaning flange portion 115, facilitating placement of the arm 50 into the resulting right-hand mounting pocket 70. A corresponding upstanding left-hand side interior gusset plate 118 includes an inward bend 120 forming an inward leaning flange portion 121, facilitating placement of the arm 48 into the resulting left-and mounting pocket 62.

Still referring to FIG. 2, the proximal frame member 64 can be mounted directly onto the mounting plates of a conventional skid loader 12 (not shown) or the like using the mounting fixtures on the front of the proximal frame member 64, without the use of any fasteners. These fixtures include a right-hand open rectangular bracket 122 fixed along a bottom edge of the proximal frame member 64 and projecting forward, and directly above it a right-hand hooked sheet bracket member 124, also projecting forward. Along a right-hand edge of the hooked sheet bracket member 124 is a right-hand locator guide member 126, which includes an outwardly flared portion 128. A symmetrical arrangement on the other side of the middle of the proximal frame member 64 includes a left-hand open rectangular bracket 130 fixed along a bottom edge of the proximal frame member 64 and projecting forward, and directly above it a left-hand hooked sheet bracket member 132, also projecting forward. Along a left-hand edge of the hooked sheet bracket member 132 is a left-hand locator guide member 134, which includes an outwardly flared portion 136. The outwardly flared portions 128, 136 make it easier to locate the proximal frame member 64 onto the skid loader 12.

Still referring to FIG. 2, the screed blade 16 and attached pre-screed screeding blade 40 cannot be pulled during screeding by the ends of the frame arms 48, 50 because they are connected to the screed blade 16 by vertical pins that allow the screed blade 16 to vibrate or float up and down in response to the hydraulic vibrators 22 (see FIG. 8) and that are not strong enough to support the screed blade 16 as it is pulled through the poured concrete 18. In any event, it is preferable to pull the screed blade 16 by forces applied adjacent to its bottom edge to prevent any tendency for the top edge to tilt forward, or disengage from the concrete forms 24, 26. Therefore, the screed blade 16 is actually pulled by a pair of pulling arms. A right-hand side pulling arm 138 has a proximal end 140 attached to the right-hand side arm 50 by a pivot pin 142 in corresponding apertures, allowing the right-hand side pulling arm 138 to pivot about the pin 142. The right-hand side pulling arm 138 has a downward directed portion 144, which allows the right-hand pulling arm 138 to pass over the top of the pre-screed screeding blade 40, then descend to a distal end 146, which is connected to a pivot pin 150 that is mounted through the reenforced pivot pin mounting bracket 58, which is fixed to the front of the vertical face of the screed blade 16, allowing the pulling arm 138 to pivot about the pivot pin 150. The distal end of the right-hand pulling arm 138 is connected near the lower edge of the screed blade 16 so that pulling forces tend to keep the screed blade 16 in contact with the concrete forms 24, 26. An exact duplicate of the right-hand pulling arm, which is the left-hand pulling arm 154, is similarly fastened to the left-hand side arm 48, being connected thereto at its proximal end to the pivot pin 156 and having a left-hand pulling arm distal end 156 connected by the pivot pin 160 to the pivot pin mounting bracket 162, which is fixed to the screed blade 40.

Referring to FIGS. 3, the concrete screed 10 is illustrated as an enlarged fragmentary view, showing the screeding portions of the concrete screed 10 more clearly than FIGS. 1, 2. The left-hand pulling arm 154 is more clearly visible, including the downward directed portion 164.

Referring to FIG. 4, the left-hand side gusset plate and arm boot 110 includes the outer upstanding vertical face portion 168 and an inwardly oriented horizontal flange portion 170, with the two portions at right angles to each other. The left-hand side interior gusset plate 118 is fixed to the horizontal flange portion 170 by welding or the like.

Referring to FIG. 5, each of the right-hand side and left-hand side hooked sheet bracket members 124, 132, as illustrated by the left-hand side hooked sheet bracket member 132 includes an upper, roughly flat horizontal portion 170, which is fixed to the top edge 172 of the upper horizontal frame member 98, and a downward bend 174, resulting in a depending flange portion, or hook portion, 176 that stands away from the front face 178 of the upper horizontal frame member 98. The two resulting hook portions allow the frame 64 to be securely suspended on the face of a typical front loader mounting system (not shown).

Referring to FIG. 6, the pivot pin 66, which is the same as all fastening pins in the concrete screed 10, is conventional and includes a head 180 that will not pass through the apertures used, a tapered nose 182 to facilitate insertion into apertures, a hole 184 perpendicular to the shaft of the pivot pin 66 for receiving a locking pin 186, which includes a pull ring 188. This pin 66 is inserted into the aperture 190, which passes through the left-hand side arm 48 adjacent to its proximal end 60. Corresponding apertures are found in both sides of the left-hand side gusset plate and arm boot 110. A flat trough portion 192 is formed between the vertical outer wall of the left-hand side gusset plate and arm boot 110 and the upstanding left-hand side interior gusset plate 118. The flat trough portion 192 serves as a downward stop for the left-hand side arm 48 to limit downward movement, as does the corresponding assembly on the right-hand side of the proximal frame member 64.

Referring to FIG. 7, the adjustment mechanism 94 includes a right-hand side bracket 194 bolted to the rear 198 of the screed blade 16 to the right of the vertical slot 95 and a corresponding left-hand side bracket 196 bolted to the rear 198 of the screed blade 16 to the left of the vertical slot 95. An adjustment screw 200 passes through apertures in a right-hand vertical plate portion 202 of the right-hand side bracket 194 and an aligned aperture in a left-hand vertical plate portion 204 of the left-hand side bracket 196 and is secured by a pair of adjustment nuts 206 abutting the inner faces of the vertical plate portions 202, 204 and a pair of locking nuts 208 abutting the outer faces of the vertical plate portions 202, 204. Loosening the locking nuts 208 allows the adjustment screws 206 to be rotated to move farther apart, thereby exerting outward force on the vertical plate portions 202, 204, causing the screed blade to bend, with its ends bending downward as shown by the deflection arrows 210, widening the adjustment slot 95. This mechanism allows the screed blade 16 to be bent to form a high line in a driveway or the like to form a crown, thereby improving drainage, if desired. When the desired deflection of the screed blade 16 has been achieved, the locking nuts 208 are tightened against the vertical plate portions 202, 204, locking the desired deflection into the screed blade 16. Reversing this sequence returns the screed blade 16 to a flat orientation.

Referring to FIG. 8, the left-hand side arm 48 is conveniently made from tubular steel or aluminum having a rectangular cross section. An end cap 212 is fixed to the open end of the left-hand side arm 48. A horizontally oriented tongue 214 is fixed to the end cap 212 and includes an aperture 216 adjacent to its distal end. A triangular reenforcing gusset 218 is fixed to the top surface of the tongue 214 and the end cap 212. The left-hand side mounting bracket 54 is fixed to a front face 220 of the vertical face 38 of the screed blade 16 and includes a horizontal portion 222 essentially even with the top edge of the screed blade 16. A vertically oriented pin 224, which is identical to the pin 66 is fixed through an aperture 226 in the left-hand side mounting bracket 54 by the nut 225 and a corresponding nut on the bottom surface of the mounting bracket 54 and passes through the aperture 216 in the tongue 214. The pin 224 is longer than the tongue 214 is thick and an upper coil compression spring 228 is placed between the top of the pin 224 and the upper surface of the tongue 214 and a lower coil compression spring 230 is placed between the lower surface of the tongue 214 and the horizontal portion 222 of the left-hand side mounting bracket 54, with the pin 224 passing through both of the springs 228, 230. The top of the pin 224 is closed off with the locking pin 186. This allows the left-hand side arm 48 to vibrate up and down in response to the vibrations of the hydraulic vibrators 22, largely isolating the right-hand side arm 50 and the left-hand side arm 48 from the up and down vibrations caused by the hydraulic vibrators 22. This mounting system reduces the mass vibrated by limiting it to essentially the screed blade 16 and its fixed attachments, transmitting little if any of the vibrating force to the frame side arms 48, 50. The right-hand side arm 50 is identically mounted onto the screed blade 16.

Referring to FIG. 9, each hydraulic vibrator 22 is fixed to the rear face 232 of the vertical face 36 of the screed blade 16 by the bolts 234. The hydraulic vibrators are conventional and their vibration rates and power are selected to be suitable for tamping the poured concrete 18 of the viscosity selected for a particular job.

Referring to FIG. 10, the horizontal triangular gusset 84 includes a horizontal face portion 236 and a downwardly oriented vertical face portion 238 that is fixed to the front face 220 of the vertical portion 36 of the screed blade 16. The mounting bracket 58 includes a horizontal plate portion 240 that is fixed to the front face 220 of the vertical portion 36 of the screed blade 16 and a vertically oriented buttressing plate member 242 located adjacent to the pin 224. This distal end 146 of the right-hand side pulling arm 138 is fixed by the pin 150 to a lower portion of the buttressing plate member 242.

The screed blade 16 is preferably made from strong aluminum alloy to save weight, while most other components are preferably made from steel to provide strength and to save money. Connections not intended to be disassembled are mostly welded, some, as shown in the drawing, are bolted. The connector pins e.g., 66, are all used for connections designed to be disassembled. In the size contemplated and illustrated herein for example, the concrete screed 10 can be broken down into pieces or segments that can be readily handled by one person and can be readily loaded into and transported by a pickup truck. It has been found that the concrete screed 10 can eliminate at least one job on small concrete jobs such as residential driveways, patios, small parking lots and so forth.

While the present invention has been described in accordance with the preferred embodiments thereof, the description is for illustration only and should not be construed as limiting the scope of the invention. Various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the following claims.

Claims

1. A concrete screed comprising:

a. a proximal frame member for attaching to a pulling means,

b. a pair of elongated spaced apart parallel frame side arms, said frame side arms further comprising a right-hand side arm and a left-hand side arm, each said side arms having a proximal end pivotally connected to said proximal frame member;

c. a screed blade connected to a distal end of said right-hand side arm and to a distal end of said left-hand side arm, with said screed blade being perpendicular to said right-hand arm and to said left-hand arm; and

d. a pre-screed screeding blade connected to a front face of said screed blade.

2. A concrete screed in accordance with claim 1 further comprising a right-hand side pulling arm having a proximal end connected to said right-hand side arm intermediate its two ends and a distal end connected to said screed blade and a left-hand side pulling arm having a proximal end connected to a said left-hand side arm intermediate its two ends and having a distal end connected to said screed blade.

3. A concrete screed in accordance with claim 1 wherein said screed blade further comprises a vertical face and a horizontal face.

4. A concrete screed in accordance with claim 1 further comprising means for bending said screed blade whereby a crown can be formed in poured concrete.

5. A concrete screed in accordance with claim 1 further comprising means for vibrating said screed blade.

6. A concrete screed in accordance with claim 5 further comprising at least one hydraulic vibrator mounted on said screed blade.

7. A concrete screed in accordance with claim 5 wherein said means for vibrating further comprises means for isolating up and down vibration of said screed blade from said right-hand side arm and from said left-hand side arm.

8. A concrete screed in accordance with claim 7 wherein said means further comprises an upper compression spring and a lower compression spring mounted on a pin with said screed blade having a tongue mounted between said upper compression spring and said lower compression spring at the distal end of each of said right-hand side arm and said left-hand side arm.

9. A concrete screed in accordance with claim 1 wherein said proximal frame member further comprises a right-hand mounting pocket for pivotal attachment of said right-hand side member and a left-hand mounting pocket for pivotal attachment of said left-hand side member.

10. A concrete screed in accordance with claim 9 further comprising means for removably attaching said proximal frame member to the mounting fixtures of a skid loader.

11. A concrete screed in accordance with claim 10 wherein said attaching means further comprises a right-hand hooked sheet bracket member and a left-hand hooked sheet bracket member, both fixed to an upper horizontal frame member of the proximal frame member and a right-hand locator guide member and a left-hand guide member fixed to said proximal frame member.

12. A concrete screed in accordance with claim 1 wherein said pre-screed screeding blade further comprises a forward projecting V-shaped screed blade having a nose portion.

13. A concrete screed comprising:

a. a proximal frame member for attaching to a pulling means,

b. a pair of elongated spaced apart parallel frame side arms, said frame side arms further comprising a right-hand side arm and a left-hand side arm, each said side arms having a proximal end pivotally connected to said proximal frame member;

c. a screed blade connected to a distal end of said right-hand side arm and to a distal end of said left-hand side arm, with said screed blade being perpendicular to said right-hand arm and to said left-hand arm;

d. a pre-screed screeding blade connected to a front face of said screed blade; and

e. a right-hand side pulling arm having a proximal end connected to said right-hand side arm intermediate its two ends and a distal end connected to said screed blade and a left-hand side pulling arm having a proximal end connected to a said left-hand side arm intermediate its two ends and having a distal end connected to said screed blade.

14. A concrete screed in accordance with claim 13 further comprising means for vibrating said screed blade and said connected pre-screed screeding blade.

15. A concrete screed in accordance with claim 14 further comprising means for isolating said right-hand side arm and said left-hand side arm from vibration of said screed blade and said pre-screed screeding blade.

16. A concrete screed in accordance with claim 13 further comprising means for attaching said proximal frame member to the mounting fixtures of a skid loader.

17. A concrete screed comprising:

a. a proximal frame member for attaching to a pulling means,

b. a pair of elongated spaced apart parallel frame side arms, said frame side arms further comprising a right-hand side arm and a left-hand side arm, each said side arms having a proximal end pivotally connected to said proximal frame member;

c. a screed blade connected to a distal end of said right-hand side arm and to a distal end of said left-hand side arm, with said screed blade being perpendicular to said right-hand arm and to said left-hand arm;

d. a pre-screed screeding blade connected to a front face of said screed blade;

e. a right-hand side pulling arm having a proximal end connected to said right-hand side arm intermediate its two ends and a distal end connected to said screed blade and a left-hand side pulling arm having a proximal end connected to a said left-hand side arm intermediate its two ends and having a distal end connected to said screed blade;

f. means for vibrating said screed blade and said connected pre-screed screeding blade and means for isolating said right-hand side arm and said left-hand side arm from vibration of said screed blade and said pre-screed screeding blade.

18. A concrete screed in accordance with claim 17 further comprising means for attaching said proximal frame member to the mounting fixtures of a skid loader.

19. A concrete screed in accordance with claim 17 wherein said vibrating means further comprises at least one hydraulic vibrator.

20. A concrete screed in accordance with claim 17 wherein said screed blade further comprises a vertical face and a horizontal face and said pre-screed screeding blade further comprises a vertical face and a horizontal face and is V-shaped.