US3528348A

US3528348A - Concrete finishing machines

Info

Publication number: US3528348A
Application number: US774078A
Authority: US
Inventors: Murray A Rowe; John E Kessel; Burnham C Loveland
Original assignee: K and R Industry Inc
Current assignee: K and R Industry Inc
Priority date: 1968-11-07
Filing date: 1968-11-07
Publication date: 1970-09-15
Anticipated expiration: 1987-09-15

Description

United States Patent In n r I Murray A. Rowe; H v V John ETIGESEE Burnham C. Loveland, Canton, South Dakota Appl. No. 774,078 Filed Nov. 7, 1968 Patented Sept. 15, 1970 Assignee K&R Industries, Inc., Canton, South Dakota a corporation of South Dakota CONCRETE FINISHING MACHINES 10 Claims, 5 Drawing Figs.

US. Cl 94/45 Int. Cl E0lc 19/22 Field of Search 94/45 46, 44

[56] References Cited UNITED

STATES PATENTS

2,83 L408 4/1958 Konway 94/45 3,368,466 2/1968 Rowe 94/45 3,382,784 5/1968 Loveiand et al. 94/45 Primary ExaminerJacob L. Nackenoff Attorney-Johnston, Root, OKeeffe, Keil, Thompson and Shurtleff ABSTRACT: A concrete finishing machine embodying a concrete-spreading unit in the form of a float or strike-off, with conveyor mechanism at one end of the surfacing unit for keeping the end thereof free of piled up concrete.

CONCRETE FINISHING MACHINES BACKGROUND OF THE INVENTION This invention relates to concrete finishing machines and, more particularly, to concrete finishing machines which are particularly well adapted for use on roadways, and the like.

It is a primary object of the present invention to afford a novel concrete finishing machine.

Another object is to afford a novel concrete surfacing unit for use in concrete finishing machines, and the like.

Concrete finishing machines of the general type to which the present invention pertains have been heretofore known in the art, such as, for example, machines of the type shown in the S. P. Bidwell U.S. Letters Pat. No. 3,208,361, issued September 28, 1965. It is an important object of the present invention to afford improvements over such machines heretofore known in the art.

In the operation of concrete finishing machines of the general type to which the present invention pertains,which have been heretofore known in the art, a concrete-spreading member in the form of a strike-off member or bull float member has commonly been moved back and forth across the width of a road, or the like, in concrete-smoothing strokes, with the machine being advanced between strokes longitudinally of the road in a direction to engage the member with a new supply of concrete to be spread or smoothed. I-leretofore, one of the problems common to the operation of such machines has been that, during such strokes, concrete tended to pile up along the end of the spreading member facing in the direction of the aforementioned advance of the machine. As a result, in the operation of such machines, heretofore it has been common practice to station a man in hip boots in the unspread conc'rete ahead of the machine, and have him manually keep the concrete from thus accumulating by the use of a hoe, or the like. Such manual spreading, of course, is relatively heavy labor, and, also, is an added expense in the operation of such a machine, requiring the services of a man for this particular operation. It is an important object of the present invention to eliminate the necessity for this manual operation.

Another object of the present invention is to enable concrete to be kept from the end of such a concrete-spreading member in a novel and expeditious manner.

In the operation of concrete finishing machines of the aforementioned type, it is common practice to roughly spread concrete ahead of the machine to a depth somewhat greater than the desired depth or thickness of the finished surface, so as to insure an adequate supply of concrete to be spread by the machine. It is an object of the present invention to enable such roughly spread concrete immediately ahead of the concrete spreading unit to be further spread and smoothed in a novel and expeditious manner.

Another object is to keep the roughly smoothed concrete moving ahead of such a spreading unit in a novel and expeditious manner.

Yet another object of the present invention is to afford a novel conveyor mechanism for preventing a build-up of concrete along such a concrete-spreading unit, during the operation thereof.

A further object is to afford a novel conveyor mechanism of the aforementioned type, which is equally effective in operation during movement of such a spreading unit in either direction across such a roadway, or the like.

Another object is to afford a novel conveyor mechanism of the aforementioned type which embodies conveyor screws constituted and arranged in a novel and expeditious manner.

Another object is to afford a novel conveyor mechanism of the aforementioned type which embodies two elongated conveyor screws which are so arranged relative to each other, and are so rotated relative to each other, that whichever direction the spreader unit is moved, transversely to the screws, the concrete engaged by the screws tends to be fed into the space between the screws as well as longitudinally outwardly therealong.

A further object of the present invention is to afford a novel surfacing unit of the aforementioned type which embodies guard members constituted and arranged in a novel and expeditious manner for guarding such conveyor screws from being damaged by bumping into objects such as concrete forms or other equipment, and the like.

Another object is to afford a novel surfacing unit of the aforementioned type wherein such guard members are so constituted and arranged as to afford effective protection against the conveyor screws being swamped during an advancing movement thereof either in a transverse or longitudinal direction.

Another object is to afford a novel concrete finishing machine which is practical and efficient in operation, and which may be readily and economically produced commercially.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings, which, by way of illustration, show a preferred embodiment of the present invention and the principles thereof and what we now consider to be the best mode in which we have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

DESCRIPTION OF THE DRAWINGS In the drawings: I

FIG. 1 is a cross section of a roadway showing a concrete finishing machine, embodying the principles of the present invention, in side elevation and disposed in operative position over the roadway;

FIG. 2 is a detail sectional view taken substantially along the line 2-2 in FIG. 1, showing the concrete surfacing unit of the concrete finishing machine in side elevation;

FIG. 3 is a fragmentary, side elevational view of a portion of the concrete surfacing unit shown in FIG. 2;

FIG. 4 is an end elevational view of the conveyor mechanism shown in FIG. 2; and

FIG. 5 is a perspective view of the concrete surfacing unit shown in FIG. 1.

DESCRIPTION OF THE EMBODIMENT SHOWN HEREIN A concrete finishing machine 1, embodying the principles of the present invention, is shown in the drawings to illustrate the presently preferred embodiment of the present invention. The machine 1 is shown in FIG. I disposed in operative position above a section 2 of a concrete roadway.

The machine 1 to which the present invention is applied is described in greater detail in the aforementioned Bidwell patent, but for present purposes it will be sufficient to point out that it includes an elongated trusswork 3, which is adapted to extend transversely of the.roadway 2 being finished, and is adapted to be moved lengthwise of the roadway in a direction transverse to the length of the trusswork by any suitable means either mechanically or by hand.

In the arrangement of the machine 1 shown in FIG. 1, vertical supports 4 are positioned on opposite sides of the roadway 2 and extend lengthwise thereof, the upper edges of the supports 4 being adapted to receive rollers 5 on the trusswork 3 to enable the trusswork 3 to be moved along the supports 4.

A surfacing unit 6 is mounted on and is suspended from the trusswork 3, FIGS. 1 and 2. The surfacing unit 6 includes an elongated main carriage 7, an elongated auxiliary carriage 8, and an elongated concrete-smoothing member in the form of a strike-off member or bull float member 9, FIGS. 2 and 5. The auxiliary carriage 8 is suspended from the main carriage 7 and is reciprocable longitudinally thereof, and the concretesmoothing member 9 is suspended from the auxiliary carriage 8 and is movable therewith, as will be discussed in greater detail presently.

The main carriage 7 includes two horizontally extending, horizontally spaced, substantially parallel outer side rails 10 and 11, and two intermediate rails 12 and 13 disposed between the side rails 10 and 11 in horizontally spaced, substantially parallel relation thereto and to each other. Two end rails 14 and 15 are connected to respective opposite ends of the intermediate rails 12 and 13 and are connected to the outer rails 10 and 11 to support the intermediate rails 12 and 13 therefrom. Preferably, the rails 1015 are disposed in uniplanar relation to each other, FIG. 5.

Two end plates 16 and 17 extend between and are mounted on respective opposite ends of the side rails 10 and 11, outwardly of the end rails 14 and 15, respectively, FIG. 5. Each of the end plates 16 and 17 has two outwardly projecting, horizontally spaced upper rollers 18 mounted on respective opposite ends thereof. The rollers 18 are so disposed on the end plates 16 and 17 that, when the concrete finishing machine 1 is in completely assembled form, as shown in FIGS. 1 and 2, the rollers 18 on the end plates 16 and 17 are disposed in position to be supported by, and ride along, the inner flanges 19 of channel shaped

side rails

20 and 21 disposed on opposite sides of the trusswork 3, to thereby support the main carriage 7 for movement longitudinally of the trusswork 3.

Each of the end plates 16 and 17 of the main carriage 7 also has two outwardly projecting hold-down rollers 22 disposed below respective ones of the upper rollers 18 in vertically spaced relation thereto. The rollers 22 are so disposed on the end plates 16 and 17 that when the main carriage 7 is supported on the

side rails

20 and 21 of the trusswork 3 by the rollers 18, in the aforementioned manner, the rollers 22 on the end plates 16 and 17 are disposed in abutting engagement with the lower faces of the webs of the

side rails

20 and 21 in position to hold the rollers 18 downwardly against the flanges 19 thereof.

The auxiliary carriage 8 is substantially rectangular in shape, and embodies four

corner posts

23, 24, 25 and 26 disposed at the respective corners thereof, FIG. 5. Each of the posts 2326 includes a substantially upright upper end por-v tion 27, and a lower end portion 28 which is downwardly and inwardly inclined transversely to the length of the carriage 8. Two horizontally extending, substantially

parallel side rails

29 and 30 extend between the upper end portions 27 of the

comer posts

23 and 24, and of the

corner posts

25 and 26, respectively. Two end rails 31 and 32 extend between the lower ends of the lower end portions 28 of the

corner posts

23 and 25 and of the

comer posts

24 and 26, respectively, and are adapted to be connected to the upper face of the concretesmoothing member 9 by suitable means such as bolts 33.

Each of the corner posts 23-26 of the auxiliary carriage 8 has an upper roller' 34 rotatably mounted on the upper end portion 27 thereof by suitable means such as pins or bolts 35, and a lower roller 36 mounted on each respective upper end portion 27 by suitable means such as a bracket 37, with the lower rollers 36 on each of the corner posts 23-26 being disposed in vertical alignment with the respective upper rollers 34 thereon. The corner posts 23-26, and the

rollers

34 and 36 are preferably so constituted and arranged that, when the surfacing unit 6 is disposed in assembled form, the upper rollers 34 on the

corner posts

23 and 24, and the upper rollers 34 on the

corner posts

25 and 26, rest on top of the side rails 10 and 11, respectively, of the main carriage 7, for movement longitudinally therealong; and the lower rollers 36 on the

comer posts

23 and 24, and the lower rollers 36 on the

corner posts

25 and 26 are disposed in engagement with the lower faces of the side rails 10 and 11, respectively, to thereby hold the upper rollers 34 down against the respective side rails 10 and 11 with which they are engaged. With this construction, the auxiliary carriage 8 is firmly secured to the main carriage 7, but is reciprocable longitudinally thereof for a reason which will be discussed in greater detail hereinafter.

The auxiliary carriage 8 also includes two

end braces

38 and 39 projecting outwardly of the end rails 31 and 32, respectively. The

end braces

38 and 39 each embodies two

side rails

40 and 41, which slope downwardly and inwardly toward each other, and are connected at their lower ends by end rails 42, FIG. 5. The side rails 40 of the

end braces

38 and 39 are connected at their upper ends to the

corner posts

23 and 26, at the 5 junctions of the upper ends 27 and the lower ends 25, thereof,

respectively; and the side rails 41 of the

end braces

38 and 39 are similarly connected to the

corner posts

25 and 24, respectively. The end rails 42 are disposed in uniplanar relation to the bottom rails 31 and 32 in position to be secured to the upper face of the concrete-smoothing member 9 by suitable means such as bolts 43. With this construction, it will be seen that the concrete-smoothing member 9 is securely supported by the auxiliary carriage 8 for longitudinal movement therewith longitudinally of the main carriage 7.

A post 44 is mounted on and projects upwardly from the upper face of the concrete-smoothing member 9, below the carriage 8, and the upper end thereof is pivotally connected by a suitable pin or bolt 45 to one end of a link 46, FIGS. 2 and 5. The other end of the link 46 is pivotally connected to one end of a crank 47, the other end of which is operatively connected to a suitable gear box unit 48 supported by a hanger 49 depending from the intermediate rails 12 and 13 of the main carriage 7. A pulley 50 is drivingly connected to the gear box 48, and is operatively connected to a motor 51 by a belt 52, the motor 51 being supported by the hanger 49. With this construction, operation of the motor 51 is effective through the belt 52, the pulley 50 and the gear box unit 48 to rotate the crank 47 and thereby cause the carriage 8 and the concretesmoothing member 9 to move back and forth longitudinally of the main carriage 7, the upper rollers 34 of the auxiliary carriage 8 riding along the respective side rails 10 and 11 of the main carriage 7 during such movement of the carriage 8.

A driving unit 53, which includes a substantially inverted L shaped housing 54 having two

legs

55 and 56, is mounted on the end of the concrete-smoothing member 9 which projects outwardly from the end brace 38 of the auxiliary carriage 8, FIG. 5. The driving unit 53 is so disposed on the member 9 that the leg 55 of the housing 54 thereof rests on the upper face of the member 9 outwardly of the bottom rail 42 of the end brace 38, with the leg 56 extending downwardly along the end face of the member 9 in juxtaposition thereto, and terminating at its lower edge 57 in uniplanar relation to the lowermost face 58 of the concrete-smoothing member 9. The leg 56 is of such size, and is so disposed, that it affords, in effect an extension of the member 9.

Two elongated conveyor screws 59 and 60 project outwardly from the side 61 of the leg 56 of the housing 54 remote from the carriage 8, in substantially horizontally uniplanar, spaced parallel relation to each other. The conveyor screws 59 and 60 are rotatably mounted in suitable means in the housing 54, such as bearings 62 mounted in the leg 56 thereof, and each has a sprocket wheel 63 and 64, respectively, mounted thereon and secured thereto within the housing 54. A motor 65 is mounted in the leg 55 of the housing 54 and has a sprocket wheel 66 mounted on the drive shaft 67 thereof. The motor 65 is drivingly connected to the conveyor screws 59 and 60 by a sprocket chain 68 which is trained over the sprocket wheel 66, the sprocket wheels 63 and 64 and an idler sprocket 69, the latter sprocket 69 being mounted on a shaft 70 which is journaled in suitable bearings 71 mounted in the leg 56 of the housing 54, FIGS. 3 and 4. The chain 68 is so connected to the sprocket wheels 66, 63 and 64 that operation of the motor 65 is effective to rotate the conveyor screw 59 in a counterclockwise direction, and the conveyor screw 60 in a clockwise direction, as viewed in FIG. 4, to thereby cause the lower portions of the peripheries of the

screws

59 and 60 to move toward each other in the direction of the arrows shown in FIG. 4.

The helical blades 72 of the conveyor screws 59 and 60 are so constituted and arranged that rotation thereof by the motor 65 during operation of the machine 1 is effective to rotate them in such direction that material engaged thereby tends to move toward the space between the conveyor screws 59 and 60 as well as longitudinally outwardly along the conveyor screws 59 and 60 away from the concrete surfacing member 9. With this construction, engagement of the conveyor screws 59 and 60 with concrete material during movement of the concrete-smoothing member 9 in either transverse direction, is effective not only to move the engaged material outwardly longitudinally of the

screw

59 or 60, but is also effective to move the material inwardly to a position wherein the two

screws

59 or 60 tend to confine it between them, and both screws are effective to move the material longitudinally outwardly.

Like the surfacing unit in the aforementioned Bidwell patent, the surfacing unit 6 is adapted to be moved lengthwise of the trusswork 3, transversely of the road surface 2, by means of chains 73, which are driven by a power unit 74, such operation being discussed in greater detail in the Bidwell patent.

The trusswork 3 is capable of being adjusted vertically with respect to the roadway 2 by means which include vertically extending rods 75 mounted in tubular members 76 and arranged to be raised and lowered by rotation of the cranks 77, H6. 1, the rollers 5 being rotatably mounted on the lower ends of the respective rods 75.

In order to accommodate the movement of the surfacing unit 6 to the desired slope of the concrete surface 2, the trusswork 3 is hinged intermediate the ends thereof as at 78. Raising and lowering of the trusswork 3 at the center thereof is then accomplished by an adjusting assembly which includes the bars 79 mounted on the trusswork 3 and through which extend a threaded rod 80. Nuts 81 engage the threaded rod 80 on opposite sides of the bars 79 so that proper adjustment thereof will change the angular pitch of the trusswork 3 at either side of the center thereof, all as more specifically described in the aforementioned Bidwell patent. Further adjustment of the trusswork 3 to achieve variations in the road contour, may be made by use of the adjusting means 82.

In the operation of the concrete finishing machine 1, after it has been adjusted to proper operative position over the roadway 2, the power unit 74 may be energized to thereby move the chains 73 and cause the surfacing unit 6 to move longitudinally of the rails and 21, transversely to the roadway 2. Such movement of the surfacing unit 6 is effective to move the concrete-smoothing member 9 in a direction transverse to its length to thereby level off and smooth the concrete engaged by the leading edge thereof, the motor 51 being energized during this movement of the surfacing unit 6 to thereby cause the auxiliary carriage 8 and the concrete-smoothing member 9 to reciprocate longitudinally of the main carriage 7 and thus effect the desired floating" action of the member 9.

During such movement of the surfacing unit 6, the excess concrete engaged by the leading edge of the concremsmoothing member 9 tends to move longitudinally thereof and around the front end of the member 9, which is the end thereof projecting outwardly from the end brace 38 of the auxiliary carriage 8. The concrete thus moving around the front end of the member 9 tends to accumulate therealong together with the unfinished concrete disposed ahead of the machine 1, and which concrete is to be smoothed by the member 9 during the next stroke of the surfacing unit 6, which is in the reverse direction across the roadway 2.

However, in the operation of the machine 1, such accumulation of excess concrete material along the front end of the member 9 is prevented by the conveyor screws 59 and 60, the

screws

59 and 60 being driven by the motor 65 during 'all such operative movements of the concrete-smoothing member 9. With this construction and operation, the excess material flows around the lower leg 56 of the housing 54 and is engaged by the

conveyor screw

59 or 60, which is disposed most closely adjacent to the leading edge of the member 9 during the particular stroke of the surfacing unit 6 across the roadway 2. As this occurs, the material is fed inwardly toward the other of the conveyor screws 60 or 59, and is fed longitudinally outwardly away from the member 9 by both of the

screws

59 and 60, where it is added to the supply of concrete material to which the concrete-smoothing member 9 will be advanced for the next stroke thereof, in the opposite direction, longitudinally of the trusswork 3. When the surfacing unit 6 reaches the longitudinal edge of the roadway surface 2 toward which it is moving, the power unit 74 and the motor 51 may be deenergized, the trusswork 3 may then be moved longitudinally forwardly along the roadway 2 and the power unit -74 may again be energized, but in the reverse direction, to move the surfacing unit 6 in the reverse direction across the roadway 2, the motor 51 again being energized for this movement of the surfacing unit 6. During each such movement of the surfacing unit 6 transversely to the length of the roadway 2, the conveyor screws 59 or 60 are effective to feed the aforementioned excess concrete material forwardly away from the member 9.

Two elongated, substantially

straight guard rails

82 and 83 are disposed on opposite sides of the housing 54, in substantially parallel relation to the concrete-smoothing member 9. The

guard rails

82 and 83 project outwardly from the driving unit 53, and the inner ends thereof are disposed in juxtaposition to respective ends of the lower rail 31 of the auxiliary carriage 8. The

guard rails

82 and 83 may be secured to the hous- I ing 54 and the bottom rail 31 by any suitable means such as, for example, welding, and a substantially vertically upright guard plate 84 extends between and is secured to the outer ends of the

guard rails

82 and 83, FIGS. 3 and 5.

The

guard rails

82 and 83 are disposed in upwardly and outwardly spaced relation to the conveyor screws 59 and 60, and the guard plate 83 is disposed outwardly of and in upwardly spaced relation to the free ends of the conveyer screws 59 and 60. The

guard rails

82 and 83 and the guard plate 84 afford guard members for protecting the conveyor screws 59 and 60 from damage by bumping against articles such as, for example, concrete forms or other pieces of equipment, and the like. In addition, they serve to aid in preventing the conveyor screws 59 and 60 from being swamped by excess concrete, the

member

82, 83 or 84 which is ahead of the

screws

59 and 60, in the direction of travel of the member 9 during a particular movement thereof, being effective to help push excess concrete material, disposed at a level above the

screws

59 and 60 along in the direction of such movement.

From the foregoing it will be seen that the present invention affords a novel concrete finishing machine wherein concrete is prevented from accumulating along the end or side of the concrete-smoothing member thereof in a novel and expeditious manner.

in addition, it will be seen that the present invention affords a novel concrete finishing machine which embodies conveyor screws constituted and arranged in a novel and expeditious manner on a concrete-smoothing member.

In addition, it will be seen that the present invention affords a novel concrete finishing machine which is practical and efficient in operation and which may be readily and economically produced commercially.

Thus, while we have illustrated and described the preferred embodiment of our invention, it is to be understood that this is capable of variation and modification, and we therefore do not wish to be limited to the precise details set forth, but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.

We claim:

1. A concrete finishing machine comprising:

a. an elongated trusswork adapted to travel in a direction transverse to the length thereof; and

b. an elongated surfacing unit comprising:

1. supporting means mounted on said trusswork for movement longitudinally thereof;

2. an elongated bull float mounted on and carried by said supporting means for movement therewith longitudinally of said trusswork in a direction transverse to the length of said bull float; and

3. conveyor screw means projecting in a generally horizontal direction from one end of said bull float for moving concrete away from said one end.

2. A concrete finishing machine as defined in claim 1, and in which:

a. said conveyor screw means comprises;

1. two elongated conveyor screws disposed in substantially parallel spaced relation to each other; and

2. means for rotating said conveyor screws in opposite directions relative to each other.

3. A concrete finishing machine as defined in claim 2, and in which:

a. said means for rotating said screws in a direction wherein the lower portions of said screws move toward each other. I

4. In a concrete finishing machine embodying an elongated trusswork for spanning a layer of concrete to be spread, and means on opposite sides of said surface for supporting said trusswork at respective opposite ends therefor for movement of said trusswork across said surface in a direction transverse to the length of said trusswork:

a. an elongated bull float;

b. means supporting said bull float from said trusswork in transversely extending downwardly spaced relation to said trusswork for movement longitudinally of said trusswork;

. said bull float having one end facing in said direction; and

. conveyor means projecting from said one end for moving concrete in said direction away from said one end.

. The combination defined in claim 4, and:

. in which said conveyor means comprises;

1. two elongated conveyor screws projecting from said one end in substantially parallel relation to each other and in longitudinal alignment with said bull float, and

. which includes;

1. means carried by said means for supporting said bull float and operatively connected to said conveyor screws for rotating the latter in a direction wherein the lower peripheral portions thereof move toward each other.

The combination defined in claim 5, and in which:

said means for rotating said conveyor screws includes a motor mounted on and carried by said bull float.

The combination defined in claim 4, and;

in which;

1. said means supporting said bull float comprises;

a. a carriage mounted on said trusswork and movable longitudinally thereof; and

b. another carriage mounted on said first mentioned carriage and movable back and forth thereon in a direction transverse to the length of said trusswork;

2. said bull float is mounted on and carried by said other carriage for movement therewith;

3. said conveyor means comprises;

a. a pair of elongated coveyor screws projecting fro m said one end in horizontally spaced, substantially parallel relation to each other; and

b. a motor mounted on and carried by said bull float and operatively connected to said conveyor screws for rotating the latter in a direction wherein the lower peripheral portions thereof move toward each other; and

b. which includes;

1. means mounted on said first mentioned carriage and operatively connected to said bull float for reciprocat ing said other carriage relative to said first mentioned carriage in said direction transverse to the length of said trusswork to thereby reciprocate said bull float longitudinally.

8. The combination defined in claim 7, and which includes:

a. guard rails mounted on said bull float and projecting outwardly from said end in upwardly and transversely outwardly, substantially parallel spaced relation to said conveyor screws; and

b. an upstanding guard plate mounted on and carried by said guard rails above and longitudinally outwardly of the ends of said conve or screws remotefrom said bull float.

9. An elongated su acmg unit for use in a concrete spreading machine which includes elongated supporting means extending across a section of concrete to be spread, said surfacing unit comprising:

a. an elongated carriage;

b. means on said carriage for supporting the same from such supporting means in transversely extending relation thereto for movement back and forth along said supporting means;

an elongated concrete-smoothing member mounted on and supported by said carriage for movement therewith in transversely extending relation to said supporting means; two elongated conveyor screws;

1. disposed in substantially horizontallyspaced, parallel relation to each other; and 2. projecting substantially horizontally outwardly from one end of said concrete-smoothing member in substantially longitudinal alignment therewith; and means supported by said carriage and operatively connected to said conveyor screws for rotating the latter in a direction wherein the lower peripheries thereof move toward each other.

10. An elongated surfacing unit as defined in claim 9, and which includes:

a. a second carriage;

l. mounted on said first mentioned carriage and movable back and forth longitudinally thereof; and

2. operatively connected to said concrete-smoothing member for supporting the same for movement with said second carriage; and

b. means on said first mentioned carriage and operatively connected to said second carriage for moving the latter back and forth along said first mentioned carriage.

UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 3,528,348 September 15, 1970 Murray A. Rowe et. :11. It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover page cancel the representative figure, and insert the figure shown below:

S 5 24 Ir ,8 s A *1 w 22 I: v v, as '2; l g 175F736 X 5; 54 5540 3528 3 5g? 7; 2 a 4 82 at; 43 5 28 5 2 4? 1 9 l z+itxflm 66 1;;36

Signed and sealed this 6th day of April 1971.

[SEAL] Attest: EDWARD M. FLETCHER, J IL, WIILIAM E. SGHUYLER, JR,

Attesting Oflioer, Commissioner of Patents.