US1533485A - Concrete-pavement-finishing machine - Google Patents

Description

April- 14, 1925. 1,533,485

G. E. WEBB I CONCRETE PAVEMENT FIISHIKNG MACHINE Filed June 15, 1921 5 Sheets-Sheet 2 I l i F1 gli; y,

April 14, 1925,

1,533,485 G. E. WEBB CONCRETE PAVEMENT FINISHING MACHINE Filed June 15, 1921 5 Sheets-Sheet 5 April I4, 1925. 1,533,485

\ l G. E. WEBB CONCRETE PAVEMENT FINI-SHING MACHINE Filed'aune 15, 1921 s sheets-sheetV 4 A y Whess.'

April 14, 1925, i G. E. WEBB CONCRETE PAVEMENT FINISHING MACHINE 'Filed June 15, 1921 5 Sheets-Sheet 5 IIIIIIIIIIII Il lbllllllklllwnlll'lllflllc Patented Apr. 14, 1925.

UNITED ,STATES a y l 1,533,485. PATENT OFFICE.

GEORGE E. WEBB, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO KOEHRING COMIANY, OF i t MILWAUKEE, WISCONSIN, A CORPORATION,

CON CRETE-:PAVEMENT-FIN ISHING MACHINE.

Application led June 15, 1921. Serial No. 477,779.

To all whom t may concern.'

Be it known that I, GEORGE E, ,Wma a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Concrete- Pavement-Finishing Machines, of which the following is a specification.

The art of building concrete roads, pavements, and the like, has progressed todayto the extent that the paving can be laid in relatively large areas daily by up-to-date machinery employed, the machinery progressing as the work proceeeds and operating over the subgrade on which the pavement is being constructed. v

It is the objectof the present invention to provide a machine for finishing the pavement, which machine is adapted to travel over the concrete aggregates after they have been laid by a suitable paving machine, strike off the said aggregates to the proper level or contour for the finished road, subject the said aggregates to pressure through l5 the medium of a ,tamping apron constituting a surface contacting pressure distributing member, and additionally subjecting the surface portion of the aggregates in contact with the said tamping apron, to Vertical vibration imparted thereto by asuitable vibrating machine coacting with the said apron. Finally, the machine is designed to apply a final finished and sealed, surface t0 the pavement by means of a'brush of suitable substance, all with a view to providing a pavement construction possessing the highest qualities of resistance to the customary wear and tear of traffic thereover, one more dense and strong than ,nowin use.

40 An essential object of the invention comprising the machine generally set forth above has .been to provide mechanical ins'trumentalities for performing practically all of the work of the machine, and under the control of a single operator. That. is

to say the machine is motor driven so as' to travel upon the road rails or forms between which the aggregates constituting the pavement are laid, its strike off board or blade is mechanically actuated, the tamping apron is carried in proper position for contact with the road surface and extending entirely across said surface, the vibrator which applies pressure, by its weights as well. as vii5 bration, to the tamping apron operates auto- .concrete pavement finishing machine emmatically, traversing the surface of the sai-d apron by passing back and forth over the latter, and the final finishing means of the machine are likewise mechanically actuated. I h ave designed ythe machine so that'the tamping apron may be elevated and thus placed in an inoperative position, facilitating movement of themachin'e when said apron is not being used for effective operation upon the road surface. i

Additionally, my invention comprehends certain features such as a special type of vibrator for the tamping apron, or surface contacting member, special control mechanisms for the carriage upon which the vibrator is mounted .and for the driving means of said carriage, -together with general control mechanisms for the movement ofthe machine as a whole when it is advanced toy la new position for effective operation of the tamping apron or member.

Other 'detailed features are comprised within the invention, including a special form of flexible tamping apron, gearing arrangements, and the like, all of which will be more fully understood uponreference'to the following description, taken. in connection with the annexed drawings, in which: i

Figure 1 illustrates a rear elevation of a bodying the essential features of vention. y

Figure 2 is a top -plan View `of the machine, certain parts, including the tamping apron, being broken away kto render clear details of construction.

Figure 3 is an end elevation of the machine illustrating' the mechanism at the power plant end particularly. v

Figure 4 is a planview, partly in section, 95 of the vibrator carriage, bringing out more 'clearly the gearing arrangements thereon.-

Figure 5 is an end view, partly in section, of the instrumentalities illustrated in Figure. A v l Figure 6 is an end view, partly in section, showing operatingmeans for temporarily elevating the tampimi apron, including the my invoperating hand whee supporting cnnections "for `Vthe tamping apron.A A

Figure 8 is a fragmentary sectional view vof a modified form of toothed wheels and 1.o

. shown in Figure 8, the track, however, being shown in section. n A Figure is a detail view of the main reversing clutch devices.

.- actuated back and forth longitudinally byc I have illustrated my invention in connection with the road bed of a typical concrete road, the subgrade of which is desig` nated A, on which subgrade A will be seen the concrete aggregates B, laid in the customary manner between road forms or rails C, which are always provided these days at the opposite sides of a road in process of construction. My; machine, as above remised, is adapted to travel upon the i orms C and comprises a main support or frame 1 made up of angle irons and channels suitably fabricated together and braced longitudinally by the trusses 2 made up of longitudinals united with vertical and diagonal struts 3.

At its opposite ends the support or frame 1 is mounted upon' wheels 4, preferably, though not necessarily, four in number, which wheels operate on the rails C. At one end of the support 1 will be provided a suitable power plant comprising the motor 5, geared, as shown in 'Figure 3,-to operate a main drive shaft 6 which is disposed parallelA with one end of the machine. By means of a suitable controlling lever 7` operating a conventional type of clutch mechanism, motor 5 may be connected to drive shaft 6, the motion of which is communicable to an adjacent one or more of the wheels 4 by means of gearing comprising the bevel pinion 8 and lbevel gear 9, see Figure 3. Under these conditions it will be evident that an operator adjacent to the motor 5 may readily cause movement of my machine bodily and advance it to a new position over the aggregates on the road bed for suitable finishing operations respecting the latter.,

At the front end of the machine are located Scrapers 10 for scraping the forms or rails C, and at this point also is located the strike off 11 which consists of a long shoe extending the whole length of the machine, operating transverse to the road subgrade, and

means of a pitman 12 operatively connected with the said shaft 6.

In rear of the lstrike olf 11 above described Iis located a roller 13 which has a peripheral contour corresponding with that which is to be imparted to the surface of the road, in this instance the road roller being of greater diameter at. the ends than at the middle. The said roller 13 assists in giving the proper' general contour to the road as the machine travels 'thereover, and after the strike off 11 has preliminarily s truck oifwth'e aggregates as the initial operatlon of finishin the surface. To drive the roller 13 I uti ize gears 14 and 15, the former operable by the leverm 16 to be disconnected frm the gear 15 and thus discontinue the rotation of said roller 13.

At the rear of the machine I provide final finishing means comprising a long brush of wire, rattan or the like, designated 17, the same" extending the whole length of the machine which corresponds in length to at least the width of the road. The brush 17 is operated like the strike off 11, except that it has a little longer stroke in respect to its longitudinal movement, a pitman 18 being the supporting and actuating means for the brush and being operated from the shaft 6.

` Between the roller 13 and the brush 17 'I have provided the primary and essential finishing mechanism of my invention. The purpose of this mechanism as outlined hereaggregates placed on the road subgrade so as to subject the surface portions of said aggregates to a certain depth to pressure,.and vibration while under such a pressure. This operation creates a relatively dense surface section for the road bed, forcing the larger aggregates well into the body of concrete and into intimate cont-act with one another. Furthermore, air is driven out of the aggregates and any voids which might otherwise remain are removed, together with excess water if any develops in the operation. The means by which I produce the finishing operation promoting the density of the surface will now be set forth.

It will be observed on reference to Figures l and 2 especially that there extends across my machine for its entire length a cable 19 which passes around grooved cable wheels 20 and 21 on the ends of the wheeled support 1, the wheel 2O being carried by a driving shaft 22 located some distance above the shaft 6, and the wheel 21 mounted upon a suitable shaft 23 atthe opposite end of the machine. A vertical shaft 24 geared at its inbefore is to operate upon the surface ofthe llO lower end to the shaft Gand having a worm n gear at its upper end co-operatingwith the worm 25 on the shaft 22, see Figure 3,

enables motion of the shaft 2 2 to be transi mitted to the shaft 6.l Figure 10 shows the clutches a and b operable by the lever 7 to drive the shaft 22 in either direction. the operation of a lever 7 the wheel 20 may ByY be driven in either of opposite directions,

'thereby to enable the vibrating means upon said carriage to operate over the entire surfaceand down upon what I have termed the tamping apron or member 29. The lever ,29 scribed, including the wheels 43 and 44 and turning the segment 36 the various levers 31 will be operated unti-l the apron 29 is low.- ered andl rests upon the concrete aggregates. The ymachine will have been previously moved alongpthe road rails C to strike off the aggregates by use of the4v strike off shoe 11, and roll them .to the general contour of the road about to be constructed, through j the action ofthe roller 13. f /f The machine being lccatedabove the section of the road to be finished, and the apron 29 .having been adjusted to itslowermost position in contact with the surface aggregates, the next thing done is to operate the lever-26 and the clutch member 27 to lcauser operation of the actuating wheel and the operating cable 19. When the cable 19 begins to operate its motion is imparted to the carriage. through themeans previously degearing, and the weights 58 beginto operate to impart verticalvibration to the carriage and the rollers 59..' This vibration is necessarily transmitted to the apron 29 and the '25 effect is an intermittent poundingor tamping operation, incident to the pounding of the rollersI 59 upon and in contact witlrthex tamping apron 29.

As the concrete'aggregates when struck 30 off are relatively loose and notr down to the finished grade, the wheels 41 of the carriage will not be in operating contact with the rails 42, but a slippage of the wheels on the rails rvvill.take place. `Gradually, however, the vibrator mechanism which I have'described, through its action upon the apron 29, will compact the concrete aggregates, rendering the same more and'more dense as the machine operates and gradually bringing them down, f

40 so to speak, to the final or finished grade for the road surface. -Necessarily, whenv the carriage which starts its `operation at either end of the machine, corresponding with either side of the road bed, has tamped, compacted, or densified, the, surface aggregates to the extent desired and required, and as limited by the degree of down movement of the rollers 41 until they Contact with the rails 42, the efficiency of the carriage and its vibrator mechanism upon that part section of the road aggregates treated, ends. Under these conditions .as the rollers 41 are constantly rotated, when they have sufficient frictional lengagement with the tracks 42 to produce traction capable of advancing the carriage, the latter moves along the main support 1, and along the tracks 42 of course, tfa new position," over the apron 29, and the loose aggregates beneath the latter. The vibrator mechanis is in'continuous operay tion, of course,` and the action of compacting, pounding, and tamping the new sectionof the road'bed, beneath the carriage and rollers 59, goes forward. In effect the" carriage. 40 will gradually move along the' machine,

and transversely ofthe road ,bed, until the' whole width of the section of the bed'beneath the apron 29 has been operated upon and j rendered ofthe required densityA desired to be produced. lWhen the carriage reaches an end of the vmachine its progressive tamp#` ing. action upon the apron 29 the operator'.

will reverse its operation through shifting f of the lever 27 and controlling clutch mechanism.

After the particular section of the road bed over which the machine .is disposed has been tamped to the desired extent bythe operation of 'the mechanism just set forth, the proper use vor manipulation of the levers 7 and 26 will cause the machine as a whole to advance until it assumes a position over a fresh untamped section of the (laid aggregates, and the tamping and compacting operation'is renewed and carried out inthe manner fully explained above. v

Should it not Jbe desired to relyupon the automatic action of the carriage, through the co-operation of the rollers 41 with the rails 42 incident to the tractionintermediate these parts, I propose a positive drive means for the carriage, which is illustrated in Figures 8 and 9. The said means includes modifying the form of the rollers 41 by toothing thewse rollersy nso that they have the form shown in Figures 8 and 9 where they are designated 41a. The teeth of the rollers 41a in lthis construction will engage'with the links of a sprocket chain 6() which will be' laid upon and fastened lto the rails 42 in any suitable manner. By utilizing the parts 41a and '60 it is evident ythat a positive feed for the carriage 4() isobtained, and under cerl tain conditions such feed may be found highly desirable. yWhen I use the positive feed 'means just set forth I prefer to employ automatic instrumentalities forreversing the cl tch lever 7 and thereby reversing the direc ion of movement of the carriage 40 when it reaches an end of the machine. With the foregoing in view I show in Figure 2 clutch reversing'sdevices which include trip levers 61 and 62 are connected to be shifted simultaneously by means of` an endless cable 63 whicln is q itself connected to pass about a. pulley wheel 64 adjacent to the lever 16 and the lever 26 and upon a shaft 65. The shaft 65 has any arm 66 connected by a linkor any suitable device .67 ,with'the lever 7. The lever 7 will be shifted in one direction to cause movement of the carriage40 in a suitably reversed direction, when the carriage 40 \26 by moving the member 27, causes driv lily conform to the struck oil' contour of the t sented.

road surface. As shown in Figure 7 the slats or boards of the apron 29 are slightly spaced apart and the apron is carried/ byl a series of angle levers 31 fixed to shafts 32. Rods 33 descend from the lower arms of the levers 31, resiliently connect the apronl with said arms through the employment of the springsj34, and ygenerallyform a suitable suspension means for the apron, connecting it to the shafts 32 aforesaid. The upper arms of the levers 31, or certain of them',

are. connected by an actuating rod 35T' On one of the shafts 32, that nearest to the motor plant end of the machine, is abtoothed sector 36 which is engaged by a. worm 37 adapted to be turned by a shaft 38 carrying the hand wheel 39. By operation of the hand wheel 39 it isfevident that the apron 29 may 'be temporarily raised so as to be elevated above the surface-of the road ag` gregates, to be placed out ofuse, or to facili- ,tate movement of the machine from one place to another.

In the operation of finishing the road surface the yapron -29 will be lowered so as to rest inl contact withalsaid surface,I and the vibrating means now to be described is set in'operation to apply pressure, and vibration to the said apron 29, to accomplish the results which' have heretofore been pre- My vibrating means comprises a carriage shown in Figures l and 2 in conjunction with the general machine, and by itself in Figures4 and 5. .This'carrige isV designed to .traverse the machine by moving back and forth along the main wheeled support l, the weight of the carriage and its parts bearing upon the apron 29, the vibrating means being supported by the carriage to impart vibration thereto, and to pressure rollers thereon, which pressure rollers are indirect engement withthe apron 29. As seen in igures 1 and 2 the carriage, designated'40,

. is equipped with lfour flanged` wheels lor roll- 40 is propelled by the `6o .ers 41, adapted to operate upon a. track 42 carried by the main supdprortl. The carriage iving cable 19 pre'- viousl described, said cable passingaround suitable grooved wheels 43 and 44, mounted upon shafts 45, suitably journaledupon the frame ofthe carriage. j The, lower bight of the cable 19 passes about the carriage operat ing wheels 43 and 44 aforesaid, the motion l of the wheels being transmitted through. the

Xshafts 45 to thewheels 41 by the use of special gearing.v This gearing may comprise the horizontal shaft 46 having bevel pinions 47 engaging corresponding pinions 48' upon 70 axles 49 t?) which the vrollers 41 are ailired` The shaft 46, one of which is illustrated fully in Figure 5, may be driven by Vmeans vsuch as a worm 50 operated by a worm gear 51 upon a central shaft 52. The shaft 52 is 75 drlven in any suitable manner from the shafts 45 through sprocket' gear and `chain connections generally designated at 53.

Mounted .upon the carriage 40 in suitable gear housings are drive gears 54 supported 80 by the shaft 52 and vcngagmgdriven gear 55, which is carried by a shaft 55 driving a weighted gear 56 operating in mesh with a corresponding welghted gear 57. The

weights on the gears 56 and 57 are desig- S5 of the gear housings areA utilized, one at each side of the carriage, and the arrangement of the gears just described is duplicated, practically speaking, in these two.90

houslngs.

The weights 58 on the weighted gears i above mentioned are so disposed that when the gears are operated from the shafts 45', the rotation of the weights 58 generates for- 95 ces whichhare substantially balanced in a horizontal direction but unbalanced in a vertical direction, the unbalanced forces operating in alternation vertically in an evi- I utilize the action of the de'nt manner. weights 58 under rotation to produce vertical vibrations of the `carriage 40 and all' of x.

its 'connected parts, substantially speaking. At thel lower portion of the carriage 4()I are m'ounted rollers 59 which operate upon the 105.

apron 29 by contact therewith, the Weight of the1 carriage being adapted to be received on the apron 29 during the finishing operation upon the road aggregates, and until the action of the pressure and yibration ofthe car-VA n0 ria-ge and its rollers 59\ has 'produced thev desired dense surface intended to be`produced by the action of the machine. The down movement of the carriage and rollers 59 and pressure thereof on the apron 29` is limited (115 by the co-operation of the rollers 41 with the rails 42, as will be'more yfully pointed out inthe general description of the operation of the invention now to be set forth.

-' It will be supposed that the machine of 120 this invention is about to be put into operation. A certain section of the concrete of I the road/"or pavement hasr beenvdeposited upon the sub-grade by em lacing the`aggre gates in`the usual way, as y a aver`or any machine such as generally-us Assuming. thatthe apron 29 has been raised and that the machine hereof hasv beeny temporarily out of use, the first thing doney by an opera# tor is to actuate the hand wheel 39 and by 13 nated at 58 nd\it will be observed that two fassa-485 f carriage may be entirely discontinued, through the discontinuance of the drive of the actuating wheel 20.

While I preferably only use the clutch re-` versing mechanism just set forth when the positive feed means for the' carriage is einployed, it will be understooduthat I can utilize said reversing ,mechanism with the type of construction or carriage driving means as first set forth herein.

It is notablethatfto maintain the cable 19 taut I preferably support the shaft 23 carrying the'wheel 21, about which the cable 19 passes, upon pivoted brackets 23, `upon which a normalpull in an outward direction is maintained' through the provision of springs 22".l Any suitable cable tensioning device, many of which are conventional in vthe various arts, may be employed.

It will be `evident that the operating` shaft 38 might 'well be actuated from the motor 5 if so desired.

By way of re-capitulation it may be observed thatfwhen, the lever 7 isr in its-neu tral position, see Figure 10, the driving of the engine to ,operate theJ shaft 22 is dis` continued andthe machine will be at` a standstill; likewise, the drive from the engine to the cable operating (wheel 20 is 1nactive. Adjustment ofthe lever 7 to bring into action one-of the reversing clutches 7a and7", see Figure 10, causes rotation of the shaft 22, and by adjustment of the lever 26 the driving f the 'wheel 20 may be obtainedthroughconnection with the clutch -, members 27 and 28. The reversing of this driveaction onthe wheel 20 is ofcourse ob-.

tained through the shifting of the jleverf7 inv reverse directions. v

The shifting ofthe lever 26 to connect the clutch members 27 and 29 is effective to transmit the'drive from the engine 'to the shaft 6, when it is desired )to advance the machine bodily upon@ the supporting rails C, the motion of the shaft 22 be1ng transmittedptothe shaft 6, under these conditions through the worm 25, shaft\ 24, and bevel gearing intermediate the shafts 26 vand 24. bviously, I members 11, 17, and 13 are operable onl when the clutch devices 27 and 29 are e ective. f

It is of importance to have four wheels for the positive driving of 4thevibrator in its progress over the flexible apron on account of the flexible n'atureof the latter. This factor renders it possible for the forward wheels of the carriage of the vibrator to at times become disengaged from the no tim'e is the positive driving` of the .caririage discontinued, something essential in the operation of the machine.

` The fabricated frame work ofthe main portab-le support .for the machine may be comprised of sections or parts susceptible that the upper layers of the aggregates are kcaused to be' arrangedso as to resist weartothe highest degree possible owing to-the fact that their flat sides are uppermost.

The carriage and vibrating/means thereon may` broadly be considered a vibrator, for they function `as such, and also viewed generally as a tamper. 7'

Notej may Be made of the fact that my. invention resides not vonly inuny general machine, as a whole, butin certain unit features thereof which are susceptible of individual employment or have functions usefulindependently of their combination with allother parts of the machine. w Having thus described I claim as new is:- 0 41'. In a concrete finishing machine, the combination of a portable support a tamping apron thereon adapted to contact with the concrete surface to be inished, a vibrator thereon operati/'ng in engagement with said apron, means to iiiove the vibrator along the apron and means for actuating the vibrator to press. on and vibrate the gates to effect movement of the tamping mechanismto a new position relatively to the aggregates operated upon.

.3. In a concrete 4finishing machine, the combination of a tamping apron adapted to contact with the concrete` surface to be finished, a vibrator operating in engagement withA said apron, a means for moving the vibrator over the apron, and common propelling means for the vibrator and the machine as a whole.

'4. .In a concrete finishing machine, the

combination of a tamping apron adapted to'contact with the concrete surface, to be' finished, a vibrator operating in engagement with Isaid a ron, a means for mov` 'ing the vibrator or elective action upon uof adjustable connection so as to vary'the j operating length of themachine to conform my invention what ios the upper surface of the apron, and comnion means to propel' the machine, actuate vthe vibrator upon the machineand effect vibratory action of the vibrator.

n 5. In a concrete nishing machine, the combination of a tamping apron adapted to v contact with the concrete surface to be finished, a vibrator operating in engagement with said apron, a means for` moving the vibrator over the apron, the machine being adapted to span a road bed, supporting means for the vibrator to y-cause movementthereof .transverse to the road bed, and v means to constantly actuatesaid supporting means.

6. In a concrete inishingmachiiie, ,the combination of a mobile support adapted to operate above a" road bed, and tamping means including almobile vibrator movable bodily on said support independently of its vibrations and means to cause said vibrator to cause pressure on a plast-ic substance and vibrate the latter while under pressure.

7. In a concrete finishing machine, the combination of a mobile support adapted to operate above a road bed, a tamping -means including a mobile vibrator/movable bodily yon said support independently of its vibrations, and a pressure'distributing. concretev contacting member carried by the support intermediate the vibrator and road surface operated on.

l8. In a concreteiinishing machine, thel combination of a mobile support adapted to operate aboye a road bed, a .tamping means including a mobile vibrator, apressure distributing concrete contacting member intermediate the vibrator androad surface operated jon, and m/eans to maintain the said member in contact with said road surface.

- and the vibrator inl engagement with said .member, and means to actuate the vibrator the surface of .thev apron, an-d vibrative independently of such movement, and a prime mover common to the propelling means and the vibrator, and adapted toV operate the latter for both its movement overgthe apron and for the vibration thereof.

' 11. In a concrete pavement finishing ma; chine, in, combination, la portable support adapted to travel" along and over the road bed to be finished, a. movable tamper on said support, a means to propel the tamper upon the support, and mean-s to automatically reverse the movement of the tamper in itsl travel upon the support.

12. In a 6concrete finishing machine, incombination, a portable support adapted to span a road bed, a strike-0E at the front of the support, a surface roller at the rear of the strike-off, a tamping mechanism in rear of ,the roller. and a finishing brush, at the rear of tamping mechanism, Iall carried by said suppor 13." In a concrete 'finishing machine, in combination. a portable support adapted to span a road bed, a strike-off` at the front of the support, a surface roller at the rear of the strike-off` a tampingI mechanism in rear of the roller, a finishing brush at the rear of. tamping mechanism, all carried by said support, and means to reciprocate the strikeoff and brush upon the support.

14. In a'concrete finishing -machine, in'

combination, a portable support adapted to span av road bed, a strike-ofiI at the front of the, support, a surface at the rear of the strike-oif.atamping mechanism in rear of the roller, a finishing brush at the rear of tamping mechanism, all carried by said support, and means common to each to operate the strike-off', tamping mechanism, and? brush. I

15. A machine as claimed in claim 1, combined with 'means to raise and lower the apron `to render it inoperative, and operative, respectively. ,y

16. A machine as claimed in claim 7, to-

getlier with means operable `to lraise and' lower the apron relatively to the road surface operated upon 17. Concrete finishing mechanism l comprising a portable support, tamping devices including va vibrator carried along vby the support, means whereby `said vibrator may beshifted bodily on the support, and means to effect its vibration, consisting of weight devices fro-operating to -create forces balanced in a horizontal direction, and unbalanced in a vertical direction, the latter forces acting to cause vibration of' the vibrator.

18. Concrete finishing mechanism comprising a portablev support, and instrumentalities thereon consisting of tamping devices including a vibrator, means whereby Jsaid vibratormay be shifted bodily, and

means to effect its vibration, consisting of weight devices co-operating to create forces balanced a horizontal direction, and unbalanced in a vertical direction, the latter forces acting to cause vibrationof the vibra tor, andoa concrete contacting member over .which the vibrator engages and operates.

19. In aconcrete finishing machine, in combination, a portable su port to travel over a road sub ade containing concrete aggregates, tamping mechanism adapted to n the upper surface area of the contacting` isaeea l travel upon said support and including a carriage having travel wheels and traction supporting means for the carriage cooperative therewith when the travel Wheels engage said traction supporting means byv lowering ried by said support, and tamping meansy mounted upon the support and shiftable over the upper surface area of the contacting apron during operation of said tamping means, with means for moving the tamping means back 'and forth While engaged with the contacting apron. i)

. 21. In a concrete inishing machine, a combination of aportable support to travel over a road bed, a concrete contacting apron carried by said support, and ramping means mounted upon the support and shiftable over apron during operation of said tamping means, with means for moving the'tamping means back and forth While engaged with the contacting apron, the last mentioned means comprising a motor on said support, driving means from said motor leading to the tamping means for shifting the same relatively to the contacting member, and for vibrating said tamping means.

22. In a concrete finishing machine, a combination of a port-able support to travel over a road bed, a concrete contacting apron carried by said support, and tamping means mounted upon the support `and shiftable over the upper surface area of the contacting apron during operation of said tamping means, with means for moving the tamping means f back and forth uWhile engaged with the contacting apron, the last mentioned means comprising a motor on said support, drivingmeans from said motor leading to the tamping means for shifting the same relatively to the contacting member,and for vibrating said tamping means, together with automatic means for reversing the direction of movement of the tamping means upon the support. y

28. In a cencrete finishing machine the combination of a portable support adapted to travel over a road bed, a concrete contacting member carried by said support, a carriage movable upon the support transversely to the road bed, a vibrator upon said carriage engaging with the contacting member and exerting a pressure thereupon, cable driving means connected With the carriage for propelling the same and connected with the vibrator for -eiiecting vibration thereof, and a power means for operating said cable means.

24. A machine as claimed in claim 23, combined with instrumentalities for reversing the movement of the carriage upon the suport. p 25. AA machine as claimed in claim 23 wherein the contacting member is made up of a series of connected boards or slats closely spaced apart.

26. Means as claimed in claim 28 combined with an elevating device for raising and lowering the contacting member and the carriage.

27. A concrete tamping mechanism comprising the carriage adapted to travel over a road bed, and a vibrating engine mounted upon said carriage, said vibrating engine comprising rotative Weight devices so arranged relatively to each other that during rotation they create unbalanced forces operatingin vertical direction, and balanced forces operating in a horizontal direction, thereby communicating alternating vertical vibrations to the carriage, and pressure means upon the carriage adapted to act with tamping effect upon the road bed through vibrative action. of said weight means.

28. A machine as claimed in claim 26 combined with* propelling means for the car` riage and the vibrating Weight devices.

In testimony whereof I affix my signature.

GEGRGE E. WEBB.

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