Vibrating Screed and Curb-Forming Apparatus

The invention relates to vibrating screed and associated apparatus for screeding concrete-formed roads, walkways, and the like, and forming associated curbing on both sides of the structure being screeded.

Lightweight, portable, vibrating, concrete screeds of the type to which the present invention is related are described in applicant's prior U.S. Pat. Nos. 4,030,873; 4,213,749 and 4,253,778. The general state of the art with respect to such type vibrating concrete screeds is believed to be fully set forth in these references and therefore will not be restated.

As another aspect of the prior art, it has been previously known to provide a screeding apparatus which is also adapted to form a curb on one side of the slab being screeded. For example, U.S. Pat. Nos. 3,224,348 and 3,377,933 teach apparatus which is designed to both screed a concrete slab and simultaneously form a curb on one side of the slab being screeded. However, it will be noted that this type of prior art represents an extremely heavy and relatively complex and therefore relatively expensive type of apparatus. As a general observation, so far as applicant is informed, it can be said that there has not been available a lightweight, portable, vibrating-type concrete screed having the ability to screed an entire roadway simultaneously with forming curbing on both sides of the roadway. Thus, it would be desirable to have curb forming apparatus which could be associated with the type of lightweight, portable, vibrating screed taught by applicant's prior patents and which could be utilized to form curbs on both sides of the roadway being screeded and with the ability to form crown and valley-type formations in the roadway contour. The provision of such an apparatus thus becomes the primary object of the present invention. Other objects will become apparent as the description proceeds.

In accordance with the present invention, a portable, lightweight, vibrating concrete screed is provided with detachable curb-forming units which may be attached to the ends of a base frame unit or to the ends of interconnected frame units. Winching mechanisms are also employed.

The base frame unit mounts a drive engine which in turn drives a flexible shaft with mounting arrangements adapted to vibrate the base frame unit throughout its length utilizing any of the various vibrating arrangements disclosed in applicant's prior U.S. Pat. Nos. 4,030,873; 4,213,749 and 4,253,778 by way of example. The curb-forming units of the invention are provided with screed blades which mate with the screed blades of the base frame unit or with the screed blades of any sub-frame unit to which the curb-forming unit of the invention is attached. A turnbuckle arrangement enables the curb-forming unit to be easily and quickly adjusted with respect to the base frame unit or individual sub-frame units to which the curb-forming unit is attached. Thus, the curb-forming units of the invention in combination with the base frame unit or the base frame unit interconnected with other individual sub-frame units may screed in various configurations, such as flat, crowned, or with a valley and the invention curb-forming units may be adjusted accordingly. Winch units may also be employed.

A hopper is provided on each curb-forming unit and which is continuously refilled by operators with concrete materials for forming the curb at each end of the screed corresponding to the sides of the concrete road being formed with the invention apparatus. Each curb-forming unit is also vibrated by means of a shaft incorporated in the curb-forming unit and connected for being driven by the vibrating shaft of the base frame unit. An additional vibrating means is driven off the vibrating shaft for vibrating the material contained within the hopper associated with each curb-forming unit. The shaft also drives winch units.

FIG. 1 is an isometric view of a vibrating concrete screed equipped with a pair of curb-forming units at its ends according to the invention and being used in a typical concrete pouring, finishing and curb-forming operation.

FIG. 2 is an end elevation view of a curb-forming unit taken generally in the direction of line 2--2 in FIG. 1.

FIG. 3 is an end elevation view similar to FIG. 2 but taken in the direction indicated by line 3--3 of FIG. 1.

FIG. 4 is a side view looking towards the rear of a curb-forming unit.

FIG. 5 is a side view looking towards the front of a curb-forming unit.

FIG. 6 is a perspective view of a curb-forming unit.

FIG. 7 is a perspective view of a non-uniform sleeve used to establish vibration in the curb-forming unit.

FIG. 8 is a perspective view of a plate and vibrating rod arrangement employed in the curb-forming unit.

FIG. 9 is a typical cross section of one type of road formed with a crown and a rollover-type curb and which is suited to being formed with the invention.

FIG. 10 is a cross section of a flat-type road with another type curb in a form suited to being formed by the invention.

FIG. 11 is a further cross section of a road having a valley and another type curb in a form suited to being made with the invention.

FIG. 12 is a partial plan view of one end of the invention screed and curb-forming apparatus illustrating a method of winching with a shaft-powered winch unit.

FIG. 13 is a perspective view of the FIG. 12 winching arrangement.

The general, elongated open frame construction of the present invention generally follows the construction previously disclosed in applicant's prior U.S. Pat. Nos. 4,030,873; 4,213,749 and 4,253,778 which will hereinafter be referred to simply as "the prior patents". The teachings of the prior patents will be deemed incorporated herein by reference and those details which are fully set forth in the prior patents and which are applicable to the present invention may be understood by making reference to the prior patents and will not be repeated here to simplify the description. As illustrated in FIG. 1, a screed 10 is formed of a base frame unit 11 constructed as previously described in the prior patents, a detachable curb-forming frame unit 12 and a detachable curb-forming frame unit 13 according to the invention. A pair of shaft-powered winching units 20, 21, such as previously described in U.S. Pat. No. 4,253,778, while not required, may also be usefully employed in conjunction with curb-forming units 12, 13. The base frame unit 11, curb-forming units 12, 13 and winch units 20, 21 can be of various lengths and can be easily and quickly connected together, in a manner to be presently described, so as to provide different lengths of screeds for spanning forms of different widths corresponding to roads with curbs and of varying overall width. Units 12, 13, 20 and 21 are typically two and one-half feet in overall length. The individual frame units may be formed of any suitable material but are preferably formed of aluminum to reduce the weight. Since the construction of the base frame unit 11 is fully described in the prior patents, the description will first turn to describing the construction of the left curb-forming frame unit 12 as representing the construction used in both of the curb-forming frame units 12, 13. Each curb-forming frame unit comprises an elongate, open structure frame such as illustrated in FIGS. 2-6. Each such structure frame includes a pair of spaced apart screed plates 15, 16 on the driven end of the curb-forming frame unit and which are illustrated as being inverted T-shaped members for the length L. The bottom screed surfaces provided by screed plates 15, 16 smoothly merge into a double-curved screed plate 17 mounted at the curb-forming end and on the bottom of the curb-forming frame unit and adapted for forming the particular desired shape curb with a "drive over" type curb being used by way of illustration. The screed plates 15, 16 together with curb-forming plate 17 extend for the length of the curb-forming frame unit and are adapted to engage and finish the concrete and form a curb as the screed is moved over the concrete in the direction of the arrow in FIG. 1. Thus, the screed plates 15, 16 and curb-forming plate 17 on each of the curb-forming frame units 12, 13 act as continuations of mating screed plates on the base unit 11. During the forming of the curbs on each side of the road being constructed, the concrete mix is feed through a later-described hopper on the curb-forming unit and through an opening provided in the curb-forming plate 17 such that the end result is to establish formed curbs on each side of the road being constructed.

Here it should be noted that according to the prior patents, the length of the base frame unit 11 was previously extended by attaching detachable screed frame units of the desired additional length. Applicant's prior U.S. Pat. No. 4,253,778 taught such an extension unit provided with a winching mechanism driven from the vibrating shaft of the base frame unit. However, the prior patents did not teach providing a curb-forming mechanism driven from the vibrating shaft as the base frame unit as with the present invention. Thus, with the present invention, the curb-forming frame units can at least partially serve both the screed function of the extension frame units of the prior patents, can be combined with the winch-type extension units of prior U.S. Pat. No. 4,253,778 and most importantly can provide detachable curb-forming mechanism for each end of the base frame unit 11. Thus, a road of substantial width can be screeded over its entire width and simultaneously have curbs formed on both sides and while being winched by winch units 20, 21.

While the open structure frame of the curb-forming frame units of the invention may take various configurations in cross section, the cross section of the curb-forming frame units 12, 13 should, of course, be compatible with the cross section of the base frame unit 11 and is illustrated and is preferably in the form of an isosceles triangle with the screed plates 15, 16 forming the lower corners of the triangle and with the ridge plate 18 forming the apex of the triangle.

The ridge plate 18 extends throughout the length of the curb-forming frame unit and is connected to the screed plates 15, 16 by suitable cross and vertical braces 22, 23. A bridging transverse bearing support 25 is fixed at opposite ends to the screed plates 15, 16 and mounts a bearing 26 which receives in a loose fitting arrangement the vibrating shaft 30 driven by the engine unit 35 which may be mounted and connected as fully described in the prior patents. Also as described in the prior patents, the semi-flexible shaft 45 of the base frame unit 11 also has a loose fit bearing arrangement in the base frame unit 11 so as to impart substantially uniform vibrations throughout the entire length of the base unit 11. The ends of the base frame unit 11 and the respective curb-forming frame units 12, 13 are provided with means for quickly and easily connecting the left and right curb-forming frame units 12, 13 on the ends of the base frame unit 11, or if base frame unit 11 has been previously extended in length to the ends of the extended base frame unit. This arrangement enables the respective screed plates, e.g., screed plates 15, 16, of the curb-forming frame units to act as extensions of the screed plates of the base frame unit 11.

The coupling arrangement is similar to that previously described in the prior patents in that the ends of the screed plates 15, 16 which are to be joined to the screed plates on the frame unit 11, 20 or 21 are provided with angle extensions 35, 36 fixed at their inner ends to the respective screed plates 15, 16 with the outer ends thereof provided with enlarged bolt holes 39, 40 for receiving connecting bolts, or the like. The screed plates of the respective curb-forming frame unit may thus be readily connected to the screed plates of the frame unit 11, 20 or 21. Also, the section of vibrating shaft 30 contained in the respective curb-forming frame unit is connected to the drive shaft 45 of the base frame unit 11 which is driven by the engine 35 through a coupling 46. Another adjustable connecting sleeve 48 joins the ridge plate 18 of the respective curb-forming frame unit to the ridge member of the frame unit 11, 20 or 21. Since the connection arrangement illustrated in FIGS. 2-6 can be generally similar to the connection arrangement illustrated in the prior patents, it is believed that the explanation given will suffice for those skilled in the art.

Referring more specifically to FIGS. 2-6, it will be seen that the short length of drive shaft 20 contained in the curb-forming frame unit 12 mounts a pulley 50 which through a belt 51 drives another pulley 52. Pulley 52 is mounted on a shaft 53 having support bearings 54, 55. Shaft 53 in turn mounts a pair of non-uniform sleeves 65, 66 which serve as eccentric weights secured by screws 67 and which are mounted so as to cause shaft 53 to vibrate when rotated. Support bearings 54, 55 are mounted on a support plate 70 which, through vibration insulating pads 75 and elongated bars 76, is secured to the curb frame unit 12 by means of plate 80 and angle supports 81, 82. Thus, when shaft 53 rotates and is caused to vibrate by means of the eccentric sleeves 65, 66, plate 70 is also caused to vibrate. Plate 70 mounts a vibratory steel rod 71 extending into a concrete mix hopper 72 having an open top and an open bottom extending through an opening provided in the double curved curb-forming plate 17. When shaft 53 rotates and vibrates so as to cause plate 70 to vibrate, rod 71 is in turn caused to vibrate so that any concrete mix placed in the hopper 72 will be vibrated as it works its way downwardly through the open bottom of hopper 72 and through an opening provided in the curb-forming plate 17. Thus, a well-vibrated concrete mix flows downwardly and as screed 10 moves forwardly forms the desired curb formation 180 on both sides of the road 85 under construction. Further, by properly adjusting the relative positions of the eccentric sleeves 65, 66 on the shaft 53, the amount of rod vibration can be increased or decreased according to the consistency of the concrete mix being used and the desired speed of operation. It will be seen then that when the segmental shaft 30 is driven by the main vibrating shaft 45 of the base frame unit 11, rod 71 will be caused to vibrate and by keeping the hopper 72 in both curb-forming units 12, 13 full of the concrete mix, such mix will be continuously vibrated as it passes downwardly through the hopper 72 and through the curb-forming plate 17 so as to form the respective curb formations 180 on both sides of the road 85 being constructed.

While methods of winching other than that illustrated can be employed, screed 10 is preferably provided with the illustrated pair of winching frame units 20, 21 of the type described in prior U.S. Pat. No. 4,253,778. Thus, with such winching frame units, screed 10 of the invention may perform a screeding operation as well as provide a mechanism by which the entire screed can be drawn over the concrete at some predetermined rate and angle and additionally form curbs 180 on both sides of the road 85 being constructed.

While illustrated in reference to forming a road with a so-called "drive over" type of curb on both sides of the road, it will be appreciated that the curb-forming unit of the invention lends itself to other curb formations and to roads which can be flat, formed with a crown or with a valley. In this regard, FIG. 9 illustrates a typical cross section of a road having a crown effect and with "drive over" type curbs formed on both sides of the road simultaneously while the road itself is being formed with the invention apparatus. FIG. 10 illustrates another typical cross section of a road with a double radius type of curb formation and a flat-type road formation. The invention apparatus of course also lends itself to forming the valley-type road as in FIG. 11 with the angled type of curb formation as further illustrated in FIG. 11.

Using the illustrated winching mechanism 20, 21, the winching cable 90 can be anchored to a "dead man" stake 91 and trained through pulleys 92, 93 at each end of screed 10.

In operation, screed 10 is supported on side forms 95, 96 and end play is reduced by vertical glide plates 97 which slide on the side surfaces of forms 95, 96. The speed and angle of winching can be controlled as fully explained in prior U.S. Pat. No. 4,253,778 and accomplished automatically while the screeding and curb-forming operations take place.

Employment of a rod to vibrate concrete is known as, for example, in prior U.S. Pat. No. 3,472,134. The unique advantage of the present invention in the embodiment disclosed resides, however, in using the engine-driven shaft 45 of base frame 11 to cause the rod vibration as well as winching and overall frame vibration. Therefore, a significant advantage of obtaining well-vibrated concrete curb mixes is assured.

In summary, it can be seen that an extremely versatile screed and curb-forming unit has been provided. A particular advantage to the trade is the fact that both curbs can be formed simultaneously with forming the road, walkway, or the like, in which curbs are desired on both sides of the structure being made whether a road, walkway, or the like. By appropriate shaping of the curb-forming plate 17 and its supporting structure, the auxiliary curb-forming unit of the invention can also be quickly adapted to other curb shapes as illustrated by FIGS. 10 and 11.