US3113494A - Finishing machine for concrete surfaces - Google Patents

Description

3 Sheets-Sheet 1 Dec. 10, 1963 R. G. BARNES FINISHING MACHINE FOR CONCRETE SURFACES Filed Sept. 12, 1958 5 w m E R 4 N .3 I m 5 e M: i 2 I m N m m A N V N 7 I 3 7 mi N E A v 1 4 Q G S i 0m 9 wt E M om l mm m WIN PM m w 13.. Q\ tm *N v )Q 06hr bv V// i I 3 2 mvm o aw mm d mi flm N6 Q; E

Dec. 10, 1963 R. G. BARNES FINISHING MACHINE FOR CONCRETE SUI RF'ACES Filed Sept. 12, 1958 5 Sheets-Sheet 2 INVENTOR Z GLE'N/V 8451/65 10, 1963 R. G. BARNES FINISHING MACHINE FOR CONCRETE SURFACES Filed Sept. 12, 1958 3 Sheets-Sheet 3 JIE IO INVENTOR. 2 Gt E/VN 54ENE5 United States Patent 3,113,494 FlNltfililNG MACHENE FGR CONQRETE SURFAQES Ralph G. Barnes, Vandalia, ()hio (4361 Wallington Drive, Dayton 40, Ohio) Filed Sept. 12, 1958, Ser. No. 755,180 Claims. (Cl. 9445) This invention relates to a finishing machine for concrcte surfaces and more particularly to a machine for finishing the surface of freshly laid concrete paving, however, the invention is not necessarily so limited.

In laying concrete paving, a screed or strike-off bar is employed to doctor the freshly laid concrete surface to the desired elevation or thickness. In conventional practice, the screed is mounted on a mobile apparatus and drawn along the freshly laid pavement immediately as it is laid. Often, to facilitate the operation of the screed it is oscillated in the direction of its length as it is drawn over the freshly laid pavement.

In addition to the use of screeds or strike-off bars for doctoring the surface of the freshly laid pavement, it has become conventional practice to vibrate the freshly laid concrete. The vibration yields two important results. One is that the concrete material is compacted to eliminate any voids in the concrete body. The other is that a layer of grout is brought to the surface of the pavement to enable fin al finishing as desired.

A vibratory screed capable of 'doctoring the freshly laid pavement to the desired thickness and also having the desired vibratory characteristics for compacting the pavement is disclosed in my United States Letters Patent No. 2,542,979 issued February 27, 1951, and entitled Screeds for Cement Surfaces. Screeds of the type disclosed in the aforementioned patent have vastly simplified the apparatus required for finishing concrete pavement. A limitation common to this type of equipment, however, is that it cannot easily :be adjusted to finish road beds of varying width and varying crown. Equip ment which can be adjusted to vary road width and crown tends to be quite massive and for this reason is unacceptable in many applications, such as bridge deck finishing.

An object of this invention is to provide a finishing machine for concrete surfaces which is sufficiently light in weight that it may be used for finishing bridge decks and the like.

Another object of this invention is to provide in a finishing machine for concrete surfaces an improved vibratory element for compacting the concrete surface.

Another object of this invention is to provide an improved strike-off bar for use in planing or trowcling the surface of freshly laid concrete pavement.

Still another object of this invention is the provision of an improved finishing machine for concrete surfaces including a strike-off bar which is adjustable to provide a curvature therein so as to establish a crown in the concrete surface being finished.

A further object of this invention is the provision of an improved machine for finishing concrete surfaces including vibratory elements for vibrating and thereby compacting the concrete body, said machine further including means for adjusting the position of said vibratory elements to accommodate a crown in the concrete surface which is being finished.

Yet another object of this invention is the provision of a finishing machine for concrete surfaces including a strike oif bar for planing the surface to the desired thickness and one or more vibratory members for compacting the surface which is to 'be finished.

Still a further object of this invention is the provision of a machine for finishing concrete surfaces including a 3,113,494 Patented Dec. 10, 1963 ice strike-oil bar which may be adjusted to provide a crown in the concrete surface and vibrating elements for cornpacting the concrete surface after it has been dootored by the strike-off bar, the machine including means for adjusting said vibratory elements to accommodate the crown established by said strike-off bar.

Still a further object is to provide a new and improved method for finishing freshly laid concrete surfaces wherethe surface is planed to provide a crown therein and vibrated so as to compact the concrete body without substantial destruction of the crown provided therein.

Gther objects and advantages reside in the construction of parts, the combination thereof, the method of manufacture, and the mode of operation, as will become more apparent from the following description.

in the drawings, FIGURE 1 is a perspective view with parts removed to reveal interior detail illustrating the machine of this invention.

FIGURE 2 is a perspective view drawn to reduced scale illustrating an inner truss member employed in the framework of the machine of FIGURE 1.

FIGURE 3 is a perspective view illustrating schematically the structural assembly of the machine of FIG- URE 1.

FlGURE 4 is a fragmentary end elevational view of the machine of FIGURE 1, with the supporting structure removed, illustrating schematically the the operative elements of the machine.

FIGURE 5 is an elevational view illustrating schematically the arrangement of vibrator elements in the machine of FTGURE 1 for vibrating a pavement having a predetermined crown.

FXGURE 6 is an enlarged front elevational view taken in the direction of the line 66 of FIGURE 1.

IGURE 7 is an end elevational view of the vibrator structure illustrated in FIGURE 6.

Fi'GURE 8 is an enlarged end elevational view taken in the direction of the line 8-8 of FIGURE 1.

FIGURE 9 is a front elevational view of the structure illustrated in FIGURE 8.

FiGU RE 10 is an enlarged rear elevational view taken substantially in the direction of the line HF-1t of FIG- URE 1.

Referring to the drawings in greater detail, the machine of this invention is illustrated in FIGURE 1. This machine is designed to move longitudinally along a highway bed behind an apparatus depositing fresh concrete to form the highway. To this end, rails 16 supported by suitable standards 12 are provided on both sides of the highway. The concrete finishing machine is provided with wheels 14 for traveling upon the rails 19.

On each end of the machine the forward wheel 14, as viewed in FIGURE 1, is supported upon an axle 16 jour' nailed in a lever arm 1'8. The lever arm 18 is pivoted on a pin 2% to a bracket 22 welded to a transverse channel member 24. The arrangement is such that pivotal movement of the lever arm 18 will function to raise and lower the transverse channel member 24 relative to the forward wheel 14.

A rear wheel 14 on each end of the machine, as viewed in FTGURE l, is supported upon an axle 2s journalled in a lever arm 28. The lever arm 23 is pivotally secured by means of a pivot pin 3% to a bracket 32 welded to the transverse channel member 24. Wheel scrapers 33 secured to the transverse channel member '24 engage the rims of the wheels 14.

The lever arms 18 associated with the front wheels 14 and the lever arms 28 associated with the rear wheels 14 are joined by a connecting link 3 The forward end of the link 34 is provided with an elongate slot 36 so that the lever arm 18 is engaged with lost motion. The assembly of lever arms 13 and 28 together with the linkage 34 is duplicated on each side of the wheels 14 at each end of the finishing machine. As clearly illustrated in FIGUIUE 1, the elongate lever arms 28 associated with the rear wheels 14 are joined by transverse rungs 29.

The arrangement is such that a pivoting movement of the rear lever arms 28 in the clockwise direction, as viewed in FIGURE 1, may be used to elevate the transverse channel member 24 relative to the highway bed, While pivotal movement of the rear lever arms 28 in the reverse direction will function to lower the transverse channel member 24. The lever arms 28 are shown in the extreme counterclockwise position at the right end of the machine in FIGURE 1 and in the extreme clockwise position at the left end of the machine in FIGURE 1.

As best illustrated at the right end of the machine of FIGURE 1, the forward wheel supporting bracket 22 is provided with a plurality of spaced holes 38 adapted to receive a lock pin 40. Similar holes and a lock pin 4i) are provided on the opposite side of the bracket 22. The lock pins 40 determine the counterclockwise position of the lever arms 18. Thus, by rotating the lever assembly in the clockwise direction, then inserting the pins 44 in any of the holes 38, then returning the lever assembly to its counterclockwise position, the lock pins 40 may be used to support the lever arms 18 in a predetermined intermediate position such that the forward end of the channel member 24 is elevated. The lost motion slot 36 in the links 34 will permit full counterclockwise travel of the lever arms 28, however, such that the rear end of the channel member 24 will not be correspondingly elevated. Similar locking mechanism is provided on the left end of the machine.

The levers associated with the wheels 14 at each end of the finishing machine thus provide a means for elevating the channel members 24 as desired and for selectively retaining the forward ends of the channel members 24 at anelevated position.

The transverse channel members 24 at either end of the machine of FIGURE 1 support a telescoping truss assembly as described in the following. Secured in spaced relation to the channel member 24 at the right end of the machine of FIGURE 1 is a rectangular outer trust assembly 42 comprising parallel upright trusses 42a and 42b. The top portions of these trusses are supported in fixed spaced relation by transverse angle bars such as identified in the drawings by reference numerals 44a, 44b, and 440. The bottom of the trusses 42a and 42b are connected in spaced relation by channel members such as illustrated at 46a and 46b in FIGURE 1.

The tranverse channel member 24 at the left end of the machine of FIGURE 1 supports a similar outer truss assembly 48 comprising parallel upright trusses 48a and 48b. These trusses 48a and 48b are supported in fixed spaced relation at their tops by transverse angle bars such as designated by the reference numerals 58a, 559b, and 590. At their bottoms, these trusses 48a and 48b are connected by transverse channel members such as illustrated at 52:: and 52b in FIGURE 1.

The rectangular outer truss assemblies 42 and 43 provided at each end of the machine of FIGURE 1 telescopically receive a rectangular inner truss assembly 54 illustrated in FIGURE 2. This inner truss assembly has been omitted from the machine as illustrated in FIGURE 1 to avoid confusion of detail. With reference to FIGURE 2 the inner truss assembly 54 comprises parallel upright side trusses 56a and 56b secured in spaced relation by angle bars indicated by the reference numerals 58a, 58b, 58c and 58d at the top, and by end braces represented by the numerals 60a and 60b at the bottom. The angle bars which make up this inner truss assembly 54 each have their flanges turned inwardly so that this inner truss assembly will slide freely in the outer truss assemblies of FIG- URE l.

The telescoping arrangement of the truss assemblies is illustrated in FIGURE 3, There it will be observed that the inner trus assembly 54 projects into the ends of the outer truss assemblies 42 and 4S much like the inner slide of a conventional match box. The arrangement is such that the length of the machine illustrated may be varied from a minimum represented by the combined lengths of the trusses 42 and 48 to a maximum represented by the combined lengths of the trusses 42 and 48 plus about four-fifths of the length of the truss assembly 54. At the maximum extension of the machine, the end portions of the truss assembly 54 must project into the ends of the assemblies 42 and 48 a sufiicient distance to provide support for the outer truss assemblies 42 and 48. At any given extension the truss assemblies are all bolted together to make a rigid structure.

The primary operative elements of the machine of this invention are illustrated in FIGURE 4. This figure depicts schematically and in phantom detail the assembly of wheels 14 with the transverse channel member 24 at one end of the machine. The machine is positioned above a concrete deposit designated by the reference numeral 62. At the forward end of the machine a strikeoff bar 64 is supported in contact with the concrete surface. This bar 64 is of a general L-shaped sect-ion and is provided with a scoop 66 at the forward end thereof for planing the surface of the concrete deposit 62.

To the rear of the strike-off bar 64 the machine supports a pair of like elongate vibratory beams 63a and 685. Only one of the beams 68a is illustrated in FIGURE 4. This beam has a substantial L-shaped section and is provided with a trailing flange 7% adapted to slap the surface of the concrete deposit 62 thereby to compact the deposit.

The machine is adapted to be moved so as to pull the strike-off bar 64 in advance of the vibratory beam 68a along the concrete deposit as it is being formed, and to this end there is provided, at each end thereof, a hand winch 72 mounted upon a post 74-. The posts- 74 are secured at the ends of the machine to the forward ends of the channel members 24. The winch cable 76 is adapted for connection to any suitable stationary object forward of the machine so that the winches 72 may be operated manually to draw the finishing machine across the surface of the freshly laid concrete deposit at the desired speed. Where desired, powered winches may be substituted for the hand winches. The use of winches is found preferable to the provision of power directly at the wheels 14- for the reason that the weight of the machine is insufficient to provide adequate traction for these wheels.

The vibratory beams 68a and 68b and the supporting structure therefor will now be described in detail. With reference to FIGURE 1, both vibratory beams are illustrated. The construction of these beams is identical. As best illustrated in FIGURE 7, the vibratory beam 68a is formed of an elongate sheet folded to substantially an L-shaped section. Preferably, the vibratory beams are formed of a flexible sheet metal material which may be heavy gauge sheet steel, as an example.

With the metal sheet of the beam 68a folded to an L-shaped section, two flanges are identifiable. One of these is the flange 7-0, which is so positioned "as to engage the concrete surface which is being finished in face to face contact. The other is a flange 89 which is oriented upright or normal to the surface of the concrete. The flanges 70 and 80 are joined by an arcuate portion or crease 82. The upper margin of the upright flange 80 is provided with a reinforcing rib 84 formed by a length of rigid pipe welded thereto.

The structure for securing the vibratory beam 68a to the finishing machine includes a clamp assembly 86 which is visible near the center of the finishing machine, as illustrated in FIGURE 1. This clamp assembly and the supporting structure associated therewith is best observed in FIGURES 6 and 7. As clearly illustrated in these figures, the clamp assembly 86 engages the reinforcing rib 84 for the vibratory beam 68a. The gripping action of the clamp assembly is controlled by a hexagonal nut 88.

With reference particularly to FIGURE 6, a bracket 90 is bolted to the clamp $6 by means of bolts 92. The bracket 9% is resiliently connected to a complementary bracket 94- by means of an elastomeric mounting member as. To this end a bolt 93 engaging the bracket 90 is embedded in the elastomeric element 96 at the top thereof. The bottom of the elastomeric element is welded to a metallic plate i452 secured to the bracket 94 by means of a bolt fill Through this construction, the bracket 90 and its complementary bracket 94 are resiliently joined together such that the bracket 9% and the vibratory beam 68a supported thereby may vibrate independently of the bracket 94.

As best seen in FIGURE 7, the bracket es supports a pair of downwardly extending angle bars 1% which, in turn, support elastorneric bumpers res. These bumpers Title function to support the vibratory beann 6811 against the drag of the concrete surface being finished.

The bracket 94 is supported in adjustable relation to the outer truss assembly 4-2 through the use of telescoping tubular members 1% and lib best seen in FIGURE 6. The member 1% is welded at its lower end to the bracket 94 and slides into the member 11%} which, as will be described subsequently, is fixedly secured with relation to the inner truss 54. The tubular members 168 and 11h? are arranged vertically. A clamp, indicated genorally by the reference numeral 112, engaging the lower end of the tubular member lid is provided for locking the iembers 1% and ill? in fixed telescopic relation.

A bushing 114 provided in the top of the tubular men ber lid rotatably receives a vertical screw lifting element 116 extending axially therein. The screw element 116 is retained at a fixed vertical elevation within the tubular member 110 by means of a collar 11% secured by a pin 12% and bearing against an annular ring 121 which, in turn, bears against the bushing TM. The extreme upper end of the screw element 116 is squared off at 122. for engagement by a suitable crank handle, not shown.

The screw element 116 engages an internally threaded portion 124 of the tubular member 168, such that upon rotation of the screw element its, the tubular member 103 may be adjusted vertically upwards or downwards depending upon the direction of rotation of the screw element 116. The tubular member 'lltl is rigidly secured as follows.

A rectangular plate 126 is welded in face contacting relation to the outer wall of the tubular member Tilt}. Bolts 128 secure the plate 126 to a transverse channel member 129 which, as appears in FIGURE 2, is an element of the inner truss assembly 54 Braces 13d and T32 Welded to the plate 126 and the channel member 129, respectively, cooperate to reenforce the connection between these members.

in the foregoing, a vertically adjustable bracket assembly with which one end of the vibratory beam 68a is secured to the outer truss assembly has been described. With reference to FIGURE 1, the extreme right end of the vibratory beam 68:: is supported by a similar vertically adjustable lifting assembly identified generally with the reference numeral 136. The lifting assembly 136 is secured to a transverse channel member in the bottom of the outer truss assembly 42. Thus the vibratory beam 68a is supported at one end by the inner truss assembly 54-, and at the other end by the outer truss assembly 42. Telescopic adjustment of the truss assemblies 42 and 54 is made permissible by a loosening of the hexagonal nuts 83 associated with the clamps 86 of the bracket assemblies supporting the vibratory beam 68a. This enables the clamps 86 to slide on the reinforcing rib $4 of the vibratory beam 68a.

In a similar manner the vibratory beam 6315, which is situated on the left end of the machine of FIGURE 1,

is supported by vertically adjustable lifting assemblies designated generally by the reference numerals 138 and Mil. The lifting assembly 138 is secured to a transverse channel member 139, which as appears in FIGURE 2, is an element of the inner truss assembly 54. The lifting assembly Mil is secured to the transverse channel member 52b of the outer truss assembly 43.

The vibratory beam 53a is set into vibratory motion by means of a vibratory element 142, illustrated best in FIGURE 1. The element 142, which comprises a rotatably mounted shaft having an eccentric weight thereon, is of conventional construction and therefore not illustrated in detail. This vibratory element is clamped against the reinforcing rib 84 for the vibratory beam 680. A motor 148 driving a belt 150 is utilized for operating the vibratory element.

As best illustrated in FIGURE 4, the motor 148 is mounted upon a plate 149. The plate 149 is supported above a parallel plate 146 by means of elastomeric spacer elements, not shown. The vibratory element 142 is clamped between the plate 146 and the reinforcing rib 84 by U-shaped brackets 1144 penetrating the flange 3t and Wrapping around the vibratory element 142 to engage the plate 14s.

A duplicate vibratory assembly, designated in FIGURE 1 by the reference numeral 152, is employed for impartin-g vibration to the vibratory beam 68b. Electrical power is supplied to the assemblies for vibrating the beams 63a and 6311 by means of an electrical generator 154 secured to the outer truss assembly 42 at the right end of the machine as illustrated in FIGURE 1. The delivery of electrical power to the vibratory assemblies is controlled by switches 156, illustrated to the right of FIGURE 1.

Due to the nature of the vibratory elements 142 used to impart vibration to the beams 63a and 6%, each of these beams is urged to vibrate in a circular pattern in a plane normal to the longitudinal axis thereof. The reinforcing ribs 84 associated with the vibratory beams prevent longitudinal flexing of the vibratory beams thereby insuring that the beams vibrate uniformly in a circular pattern throughout their length.

The operation of the finishing machine is such as to draw the vibratory beams 68:; and 681; over the surface of fresh concrete with the flanges 7d of the beams trailing the upright flanges 85 thereof. Due to the drag of the concrete on the trailing flange 7-8, the upright flange 8t) is drawn against the adjacent bumpers ms. The bumpers Hi6 yield under the force created by drag on the flanges '70 until the elastic restoring forces therein counteract the drag force. These opposing forces bias the flanges Ell to an equilibrium vertical position. The bias is resilient or yieldable such that these flanges remain free to vibrate. Since the impressed vibration is rotary the flanges ill will vibrate with a rotary movement.

The rotary vibratory movement of the flanges fill is transmitted to the flanges 70. These flanges therefore also vibrate with a rotary motion. Thus, the flanges 7i will oscillate with a generally horizontal side to side motion and will simultaneously execute a vertical pivotal movement. Due to the vertical pivotal movement, the arcuate creases 82 between the flanges 70 and 80 of the beams 625a and 68b undergo repeated flexing such that the angle between the flanges 70 and 80 increases and decreases cyclically. It is to be observed that the creases 32 are in the form of a gentle curve as opposed to a sharp angular bend. This spreads the flexure of the metal in the creases over a wide area thereby reducing the susceptability of the metal in the creases to work hardening and fatigue.

Preferably, the rest angle between the flanges 7t and 86 is about 93. An angle in excess of 90 causes the flanges '76} to be inclined to the surface of the concrete deposit so that they will ski over the concrete surfaces.

7 The skiing action of the flanges 7t enables the vibratory deposit so that they will ski over the concrete surface. with a minimum of distortion of the crown placed thereon.

In practice a condition of resonance develops between the vibratory movement of the beams 68a. and 68b and the impressed vibratory frequency. The condition of resonance is particularly noticeable in the flanges 70 which vibrate with a much greater amplitude than that found in the movement of the vibratory element 142.

The large amplitude vertical vibration of the flanges 70 produces a slapping or Whipping action such that the surface of the concrete deposit 62 is repeatedly struck with great force. This induces vibration in the concrete body as illustrated schematically in FIGURE 4. Preferably, the impresed vibratory frequency is in the range of 70*9O cycles per second.

The vibrations induced in the concrete body are duofunctional. First, they compact the freshly laid concrete eliminating any voids therein. Second, a layer of grout is brought to the surface of the concrete deposit to enable final finishing to be done quickly.

The construction of the strike-off bar 64 and the supporting structure therefor will now be described. As appears in FIGURE :1, the strike-off bar 64 is formed of a number of segments identified by the numbers 170a, 170b, 170b, 170d, 170e and 1707. The extreme left end of the strike-ofi bar 64, as viewed in FIGURE 1, connects to a pair of baffles numbered 172a. and 17 2b. The baffle 17% serves as a scraper for the left rail on which the machine rides. Similar baflles are provided at the opposite or right end of the strike-01f bar.

The segment 170a. of the strike-off bar is illustrated in detail in FIGURES 8 and 9. Referring to FIGURE 8, which shows the segment 170m in end elevation, it is seen that this segment comprises a unitary sheet folded so as to have substantially right angularly disposed flanges 174 and 1178. The flange 174, which is oriented vertically, has its lower margin struck outwardly to form a scoop or inclined plane 176. The segments 170b, 1700,

170d, 170e, and 1707 are similarly formed and, as appears in FIGURE 1, the inclined planes 176 in each segment align to form a continuous inclined plane sur face for scraping or planing the surface of the concrete deposit over which the machine is moved.

Referring to FIGURES 8 and 9, the segment 170a of the strike-off bar is reinforced by right angular rib elements 180 and 182 formed from lengths of angle bar welded together. These rib elements are welded in place on the segment 17051.. Other reinforcement, not illustrated, may be provided as required.

The structure for supporting the segment 170a. with respect to the finishing machine includes a hinge element 1 84 welded to the reinforcing rib elements 180 and 182. This hinge element is pivotally engaged by a vertically disposed tubular member 186 provided at its lower end with a clevis 188. The tubular member 186 fits telescopically into a larger tubular member 190 and is threadedly engaged by a vertical screw lifting element 192. The assembly of telescopic tubular members 1 86 and 190 is substantially identical in construction to the assembly of telescoping tubular members 108 and 110 illustrated in FIGURE 6 and described hereinbefore.

The tubular member 190 is connected to a channel member 198 which is part of the outer truss assembly 48. To effect this connection a plate 194 is Welded in face contacting relation to the tubular member 190 and bolted to the channel member 198 with bolts 196. A brace 200 welded to the plate 194 and a brace 202 Welded to the channel member 198 cooperate to strengthen the connection between the channel member 198 and the tubular member 190.

It is evident from the foregoing construction that rotation of the screw lifting element 192 may be employed to raise and lower the segment 17% of the strike-off bar 8 64. In a similar manner, the segment 17012 is connected by means of an adjustable assembly of telescopic tubular lifting members designated generally by the reference numeral 210 to a transverse channel member 211 .of the outer truss assembly 48. The segment 1700, which is substantially at the center of the strike-off bar 64, is secured by means of an adjustable assembly of telescoping tubular lifting members designated by the reference numeral 212 to the transverse channel member 129 of the inner truss assembly 54-. The segment 1702 is secured to the transverse channel member 46a of the outer truss assembly 42 by means of an assembly of telescoping tubular lifting members designated by the reference numeral 214. The assembly 214 is shown in fragmentary detail. The segment 17th of the strike-off bar 64 is secured by means of an adjustable assembly of telescoping tubular lifting members designated gencrally by the reference numeral 216 to a transverse channel member 218 of the outer truss assembly 42.

Adjacent pairs of the segments 17tPa-f are joined in the manner illustrated in FIGURE 10. Specifically, this figure shows the connection between the segments 17% and To effect the connection, the segment 17012 is provided at its end with a right angular reinforcing rib 220 formed 10f angle bar stock. A short distance inwardly of its end, the segment 17th is provided with a similar right angular reinforcing rib 222. When the segments 170a and 179 are butted together in end-to-end relation, the reinforcing ribs 229 and 2.22 are distributed in parallel relation with a small gap tberebetwecn. The reinforcing rib 220 is so positioned on the segment 170s that it overlaps the seam between the segments 17% and 170].

The rein-forcing ribs 223 and .222. are bolted together at their opposite ends by means of bolts 22 i and 226. A hearing 228 is positioned between these two reinforclinig ribs in the corners thereof. The bearing 228 is secured between the ribs by means of a bolt assembly, not illustrated, the bolt of this assembly passing through the upright flanges of each of the ribs 226 and 222 and through the center of the bearing 228..

The opposite ends of the bearing 228. are tapered so as to reduce the area of contact between the ends of the bearing 2128 and the reinforcing ribs 220 and 222. By virtue of this reduced area of contact, the segments 170.2 and 1709 are permitted limited pivotal movement on the bearing 22-8 whenever the bolts 224 and 226 connecting the ends of the reinforcing ribs 22% and 2.22 are loosened. This type of connection enables the segments 17% and 1701 to be adjusted to a desired angular relationship with the bolts 224 and 226 loosened, then to be fixed at that angular relationship by tightening the bolts 224 and A similar connection is provided between all adjacent segments of the strike-cit bar. At those junctions where the segments are supported by an adjustable lifting support, such as the junction between the segments 17% and 1706, the upper bolt 22.4 is replaced by an unthreaded shaft. As a result these adjacent segments are, at all times, free to pivot with adjustment of the lifting support. The arrangement is such that by loosening the connecting bolts between all of the segments of the strike-off bar and by thereafter adjusting the elevation of the strikeoff bar by means of the adjustable lifting supports for the segments 170a, 1170b, 1700, 1702 and 170 the strike-off bar may be formed to a desired curvature in the vertical plane. Once the desired curvature has been established, it may be fixed by tightening the bolts joining the ends of adjacent segments. With this type of assembly, the strike-off bar 64- may be adjusted within reasonable limits to place any desired crown on the concrete surface which is to be finished.

I The adjustable lifting supports for the strike-off bar 64 have a secondary function. It is not possible as a practical matter to preserve the adjustment of the finishing machine indefinitely. The adjustable lifting supports permit adjustment to correct small errors in the alignment of the strike-off bar as they develop.

The operation of the finishing machine will now be described. With the finishing machine situated upon rails over the surface which is to receive a concrete finish, the strike-oil bar 64 is adjusted to provide the desired crown in the concrete surface by adjusting the various adjustable telescoping lifting assemblies 1%, 211i 212, 214- and 216. The bolts connecting the ends of the strike-cit bar segments, which are loosened to permit the initial adjustment of the strike-off bar, are thereafter tightened to fix the curvature of the strike-off bar. The strike-off bar is then adjusted to the desired elevation relative to the ground through adjustment of the pins 40 in the holes 38 of the brackets 22 at the opposite ends of the finishing machine. This latter adjustment is accomplished without altering the crown setting. Usually, the strike-oil bar is set /2 inch or so above the desired surface elevation to allow for subsequent compaction.

The vibratory beams 63a and 6% are adjusted to accommodate the crown of the concrete surface. This adjustment is eilected by adjustment of the telescoping lifting assemblies 11-6, 136, 1 38, and l id). FIGURE 5 illustrates the manner in which the vibratory beams 68:: and 68]) are adjusted to accommodate the crown of the concrete surface. In this figure the shape of the crown is illustrated schematically by the broken rcuate line 249. The vibratory beams 68a and 6812, which are always maintained in overlapping end-to-end relation, are adjusted so that the point at which their flanges 7% cross is at the top of the crown when the opposite ends of the beams 68a and 68b also lie on the surface of the crown. Preferably, the aforementioned points are set about Mr inch below the ultimate crown surface. This insures effective action of the vibratory beams throughout the entire width of the concrete surface being formed. The arcuate crease 82 in each vibratory beam functions to guide the upper portions of the concrete surface under the flange 70.

Following the adjustments outlined in the foregoing, the generator 154 is put into operation so that the vibratory beams 63a and 68b are continuously vibrated. As concrete is poured forward of the machine, the machine is advanced at a uniform rate to finish the concrete. Preferably, the elevation of the concrete placed in front of the machine is such that a roll of approximate 2 inches height will be maintained in front of the strike-oil bar at all times.

it has been found that this concrete finishing machine will operate continuously for long periods of time with out attention. At any time, as for example when it may be desired to make small adjustments on the machine or to discontinue the operation of the machine, both the strike-off bar 64 and the vibratory beams 68a and 63b may be picked up oil the concrete surface by movement of the lever arms 23 at the opposite ends of t e finishing machine in the counterclockwise direction as viewed in FIGURE 1.

As described hereinbefore, the overall length of the concrete finishing machine is variable due to the use of telescoping truss assemblies. The overall length of the strike-off bar 64 is adjustable by adding or removing segments, like the segment 170d, which are of varying length. These segments may be added on either side of the segment 170C. Ordinarily, a suflicient number of extra segments is kept on hand so that the strike-off bar 64 may be adjusted to any of the standard road widths between the maximum and minimum widths to which the present concrete finishing machine may be adjusted.

The vibratory beams 68a and 68b each have a length slightly exceeding one-half the maximum length of the finishing machine. As a result, even when the machine is adjusted to its maximum width, there will be a partial overlap between the ends of the vibratory beams 68a and.

68b. As noted hereinbefore, the clamping assemblies 86, engaging the overlapping ends of the vibratory beams, must be loosened so that they may slide upon the reinforcing ribs 84 whenever the overall length of the concrete finishing machine is changed.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. An apparatus for finishing the surface of fresh concrete comprising a vibratory beam, structure for supporting said beam upon the concrete surface, said beam comprising a pair of elongate substantially planar flanges, one of said flanges adapted to be normal to the concrete surface and the other of said flanges adapted to be substantially parallel to and in contact with said concrete surface, there being a margin of said one flange in proximate relation to a margin of said other flange, a flexible arcu-ate portion uniting said proximate margins whereby said beam has a substantially L-shaped section, said structure including means engaging said one flange and resiliently supporting said beam from said structure for vibratory movement relative to said structure, a vibrating unit for transmitting vibratory motion to said one flange, said arcuate portion having a flexibility sufficient to permit resonant vibration of said other flange about a longitudinal axis defined by said flexible portion at the frequency of the impressed vibratory motion, said flanges being sufliciently similar in width to accomplish such vibration, and reinforcing means engaging said beam and extending longitudinally along the length thereof to prevent resonant transverse vibration of said beam except at frequencies higher than that of the impressed vibration.

2. An apparatus for finishing the surface of fresh concrete including a vibratory beam, said beam comprising an elongate flexible metallic sheet provided with a longitudinal arcuate crease forming two angularly disposed flanges thereof, one of said flanges being vertical and the other substantially horizontal, means providing a reinforcing rib along the free margin of the vertical flange, and vibratory means engaging said reinforcing rib for imparting vibration to said beam, said means vibrating normal to the longitudinal axis of said beam, said reinforcing rib imparting suflicient rigidity to said beam to prevent resonant transverse vibration of said beam except at freqeuncies higher than that impressed by said vibratory means, and said arcuate crease having sufficient flexibility to permit resonant vibration of said horizontal flange about a longitudinal axis defined by said crease at the frequency of vibration impressed by said vibratory means, said flanges being sufficiently similar in width to accomplish such vibration.

3. llhe apparatus according to claim 2,. wherein said substantially horizontal flange is disposed in trailing relation to said vertical flange at an angle thereto exceeding the arcuate crease therebetween functioning to guide upwardly projecting portions of said concrete surface under said substantially horizontal flange.

4. In an apparatus for finishing the surface of a fresh concrete deposit, an elongate beam, structure for supporting said beam parallel to the surface of said deposit, and means for vibrating said beam, the improvement wherein said beam comprises an elongate strip of flexible metallic material having an arcuate longitudinal crease therein forming two angularly disposed flanges thereof, and means providing an elongate reinforcing rib along the free margin of one of said flanges, said structure including resilient mounting means engaging said reinforcing rib to support said beam for independent vibratory motion, said one flange adapted to be oriented substantially normal to the plane of said concrete surface and supporting said vibratory means, the other flange having one face adapted to contact said concrete surface, said reinforcing rib imparting suflicient rigidity to said beam to prevent resonant transverse vibration of said beam except at frequencies higher than that impressed by said vibratory means, and said arcuate crease having sufficient flexibility to permit resonant vibration of said other flange about a longitudinal axis defined by said crease at the frequency of vibration impressed by said vibratory means, said flanges being sufficiently similar in width to accomplish such vibration.

5. An apparatus for finishing the surface of a fresh concrete deposit including a vibratory beam, structure for supporting said beam upon said deposit, said beam including a pair of elongate flanges of flexible material arranged at an angle and united by an arouate flexible portion so as to have a substantially L-shaped section, and means providing an elongate reinforcing rib along the free margin of one of said flanges, vibratory means engaging said rib to vibrate said beam, said structure including a supporting bracket, a complementary bracket engaging said reinforcing rib, and an el-astomeric body joined to both said brackets providing a resilient connection therebetween, said brackets supporting the reinforced flange of said beam substantially normal to the surface of said concrete deposit, the other flange of said beam adapted to be disposed in face contacting relation to said concrete deposit, said reinforcing rib imparting suflicient rigidity to said beam to prevent resonant transverse vibration of said beam except at frequencies higher than that impressed by said vibratory means, and said arcu ate flexible portion having sufiicient flexibility to permit resonant vibration of said other,

12 flange about a longitudinal axis defined by said flexible portion at the frequency of vibration impressed by said vibratory means, said flanges being sufficiently similar in Width to accomplish such vibration.

References Cited in the file of this patent UNITED STATES PATENTS 1,386,348 Mlaxon Aug. 2, 1921 1,388,690 Baker Aug. 23, 1921 1,619,083 Maxon Mar. 1, 1927 1,662,257 Valerio Mar. 13, '1928 1,782,707 Bayiley May 25, 1930 1,987,398 Gardiner Jan. 8, 1935 2,072,479 Hadley Mar. 2, 1937 2,094,910 Baily Oct. 5, 1937 2,145,959 Venable Feb. 7, 1939 2,150,618 Blackwell Mar. 14, 1939 2,219,246 Jackson Oct. 22, 1940 2,306,125 Jackson Dec. 22, 1942 2,332,687 Baily Oct. 216, 1943 2,346,378 Jackson Apr. 11, 1944 2,351,593 Barber June 20, 1944 2,542,979 Barnes Feb. 27, 1951 2,681,231 Kondracki June 15, 1954 2,693,136 Barnes Nov. 2, 1954 2,951,426 Pollitz Sept.,6, 1960 FOREIGN PATENTS 831,023 France May 30, 1938 142,458 Australia July 25, 1951 OTHER REFERENCES Construction Methods and Equipment, September 1953, page 128.

Claims (1)

1. 2. AN APPARATUS FOR FINISHING THE SURFACE OF FRESH CONCRETE INCLUDING A VIBRATORY BEAM, SAID BEAM COMPRISING AN ELONGATE FLEXIBLE METALLIC SHEET PROVIDED WITH A LONGITUDINAL ARCUATE CREASE FORMING TWO ANGULARLY DISPOSED FLANGES THEREOF, ONE OF SAID FLANGES BEING VERTICAL AND THE OTHER SUBSTANTIALLY HORIZONTAL, MEANS PROVIDING A REINFORCING RIB ALONG THE FREE MARGIN OF THE VERTICAL FLANGE, AND VIBRATORY MEANS ENGAGING SAID REINFORCING RIB FOR IMPARTING VIBRATION TO SAID BEAM, SAID MEANS VIBRATING NORMAL TO THE LONGITUDINAL AXIS OF SAID BEAM, SAID REINFORCING RIB IMPARTING SUFFICIENT RIGIDITY TO SAID BEAM TO PREVENT RESONANT TRANSVERSE VIBRATION OF SAID BEAM EXCEPT AT FREQUENCIES HIGHER THAN THAT IMPRESSED BY SAID VIBRATORY MEANS, AND SAID ARCUATE CREASE HAVING SUFFICIENT FLEXIBILITY TO PREMIT RESONANT VIBRATION OF SAID HORIZONTAL FLANGE ABOUT A LONGITUDINAL AXIS DEFINED BY SAID CREASE AT THE FREQUENCY OF VIBRATION IMPRESSED BY SAID VIBRATORY MEANS, SAID FLANGES BEING SUFFICIENTLY SIMILAR IN WIDTH TO ACCOMPLISH SUCH VIBRATION.

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