Abstract:
A roller carriage assembly for a road surface finishing machine of the type having an elongated main frame is disclosed. The assembly features a vibrating drum or roller wherein rotating eccentric weights used to generate vibrations can be rotated at speeds which are independent of the speed of roller rotation to thus permit the finishing of extremely low slump concrete. The assembly employs a scissors extender system which permits rapid and precise changes in the level of the roller relative to the main frame without affecting the attitude of the former relative to the latter. The scissors extender system is locked in place by a rotating locking mechanism and is rigidified by the use of four chains disposed at the corners of the system and strung between upper and lower plates between which the scissors mechanism operates.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to road and other surface finishing machines. More specifically, the invention relates to a roller carriage assembly which is movably connected in the usual manner to the conventional double frame of such a machine for movement back and forth across such a surface to consolidate and finish the same with a vibrating drum or roller, including means for changing the level of the roller relative to the double frame as will be necessary when adapting the machine to different job sites. 
     Generally speaking, road surface finishing machines, having an elongated double main frame adapted to span above and across a roadway or other surface being finished from which is suspended a roller frame containing a vibrating drum or roller adapted to move back and forth along the main frame and roll across the surface or placed to condolidate and finish concrete or other materials freshly poured or placed thereabout, have long been known and used in the prior art. The double frames of such machines contain legs or standards on each end thereof, on the lower ends of which roller assemblies are connected. The roller assemblies ride upon tubular rails laid along both sides of the surface being finished. Accordingly, the double main frame of the machine can thus be rolled along the guide rails to advance the same along the surface as concrete or other material is being poured or placed in front thereof, while the roller frame moves along the double frame back and forth across the same along the leading edge of the freshly placed material to permit a vibrating roller to consolidate and finish the same. Examples of such prior art machines are the Series  36 concrete finishers manufactured by Bidwell Division of CMI Corporation, Canton, S. Dak. 57013, and the C-450-X finisher as manufactured by Gomaco Corporation, Ida Grove, Ia. 51445. 
     One of the problems encountered using these prior art machines with conventional roller carriage assemblies is that it is extremely difficult to change the level of the roller relative to the main frame which usually must be done when adapting such machines to different job sites. Another problem encountered using the conventional assemblies is the relatively narrow range of vibrating frequencies that can be obtained in the rollers due to the fact that the rotating eccentric weights used to generate the vibrations are dependent upon the speed of the roller itself. 
     By means of my invention, these and other difficulties encountered using conventional road surface finishing machines and roller carriage assemblies are substantially overcome. 
     SUMMARY OF THE INVENTION 
     It is an object of my invention to provide a novel roller carriage assembly for use with a double main frame of an otherwise conventional surface finishing machine. 
     It is a further object of my invention to provide a highly efficient vibrating roller assembly for a concrete finishing machine which will permit the consolidation and finishing of extremely low slump concrete. 
     It is yet another object of my invention to provide a roller carriage assembly for suspension from a double main frame of an otherwise conventional surface finishing machine wherein the level of the roller carried by the assembly relative to the main frame is readily adjustable. 
     It is also an object of my invention to provide a novel scissors extender system for adjusting the level of a finishing roller relative to the main frame from which it is suspended. 
     Briefly, in accordance with my invention, there is provided a roller carriage assembly for a finishing machine for a road or other surface of the type which includes a main frame adapted to extend above and across the surface being finished. The roller carriage assembly includes an upper frame mounted in the main frame for movement back and forth across the surface being finished. The assembly also includes a roller means for rolling upon and across the surface being finished. Lastly, the assembly includes means connecting the roller means to the upper frame for selectively changing the vertical distance between the upper frame and the roller means while maintaining a fixed attitude of the roller means relative to the upper frame. 
     These and other object, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description and attached drawings upon which, by way of example, only a single preferred embodiment of my invention is shown and described. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a side elevation view of a road surface finishing machine containing a height adjustable, vibratory roller mounted in a horizontally movable roller carriage assembly, thus illustrating one preferred embodiment of my invention. 
     FIG. 2 shows an enlarged side elevation view of a portion of the machine, roller and carriage assembly of FIG. 1, the same as viewed in the latter figure except with certain surface parts torn away for viewing internal features. 
     FIG. 3 shows a cross-sectional and elevation view of a portion of the roller and carriage assembly of FIG. 1 as viewed along cross-section lines 3--3 of the latter mentioned figure. 
     FIG. 4 shows a left end elevation view of the roller and carriage assembly of FIG. 1 looking in a direction opposite that of FIG. 3 with the auger mechanism of FIG. 1 torn away. 
     FIG. 5 shows an exploded perspective view of a portion of the carriage assembly of FIG. 1 illustrating the construction of a locking mechanism for a scissors extension system used in the carriage assembly. 
     FIGS. 6-11 show top plan views of the various arms of the scissors extension system used in the carriage assembly of FIG. 1 with reinforcing members adjoining the different arm pairs. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawing figures, there is shown, in one preferred embodiment of my invention, a roller carriage 10 movably mounted on a conventional double frame 12a,b of a road surface finishing machine. The assembly 10 is suspended from the frame 12a,b by means of rollers 14a,b connected to an upper frame 13 which travel along tracks formed by two angle brackets 16a,b such that the assembly 10 can be moved from one side to the other and back across a road surface 18 to finish the same. A motor 20 and gear and chain assembly 22 drive the carriage 10 along the brackets 16a,b in the usual, well known manner. The frame 12a,b is elevated above the roadway 18 by means of two pairs of standards 24 located on opposite end portions thereof, only one of which pairs is shown. The standards 24 contain roller assemblies 26 which engage and roll along steel tubes 28 which extend along the top of a series of concrete barriers 30 positioned end-to-end along both sides of the roadway being paved and finished. The upper end portions of the standards 24 likewise contain rollers 32 and 34 which are rollably mounted on steel tubes 36 and 38, respectively. The tubes 36 and 38 are welded to upper and lower surfaces of the frames 12a,b. Thus the standards 24 can be adjusted to roll upon tubes extending along spaced, parallel sets of barriers having different distances between the sets to permit finishing roadways of different widths. 
     The carriage 10 includes the upper frame 13, a flat rectangularly shaped upper plate 40 fixedly connected to the underside of the upper frame 13, and a scissors extension mechanism 42 pivotally connected to and between the upper plate 40 and a lower plate 44. Also included is a roller housing 46 attached to the lower plate by means of suitable threaded fasteners which extend through a series of cylindrically shaped shock absorbers 48. the shock absorbers 48 may be made of rubber, plastic or other suitable compressible, resilient material. A hollow, elongated, cylindrically shaped roller 50 is rotatably mounted to end walls 52 and 53 of the roller housing 46. An elongated steel shaft 54 extends along the longitudinal axis of the roller 50 and connects to the end walls of the roller 50 for free floating rotation independent of the rotation of the latter. 
     A first vibratory member or eccentric mass 56 is fixedly connected to the shaft 54 for rotation with the latter. A pair of screws 57 located in the collar of the mass 56 can be loosened to permit placement of the mass 56 at any desired position along the shaft 54. At least one of the end walls of the roller 50 should be removable to permit access to the mass 56 for adjustment of the latter. In the present example of the invention, both end walls of the roller 50 are shown as being removable by means of bolts (See FIG. 2). A companion or second eccentric mass 58 (FIG. 2 only) is likewise fixedly mounted in line with the longitudinal axis of the shaft 54 on the outside surface of the sidewall 52 and outside of the roller 50. A hydraulic motor 60 located on an inside surface of the sidewall 53 drives a sprocket and chain 62 which, in turn, rotatably drives the roller 50 and an auger 64 located at the front of the roller 50. Similarly, a hydraulic motor 66 coupled to the shaft 54 rotates the latter and the eccentric masses 56 and 58 independently of the rotation of the roller 50 at any desired speed within a range of speeds depending upon the characteristics of the motor for selecting any desired frequency of vibration desired within a range of frequencies. I have found that by placing the mass 56 closer to the wall 53 than to the wall 52, most of the large amplitude vibrations will occur along a front end portion of the roller 50 where the concrete to be finished is deepest and tend to dampen out toward the rear end of the roller 50, all of which is highly desirable. 
     The extension mechanism 42 is expanded and contracted vertically by adjusting an elongated threaded bolt 68 to respectively lower and raise the roller 50 relative to the upper frame 13 from which it is suspended. The bolt 68 extends across the mechanism 42 through cross members 70 and 71. Once the desired level of the roller 50 is precisely set with the bolt 68, a series of four chains 72 which are welded on their lower ends to bars 74 affixed to the four corners of the plate 44 are drawn tight by hand and attached along their upper ends to hooks 76 connected to angles 77 and 78 at the front and rear corners of the upper plate 40. Once the chains 72 are hooked, the bolt 68 can be further turned until the chains 72 are drawn tight to thus rigidify the roller carriage assembly 10. 
     The mechanism 42 can be locked to maintain the roller 50 at the desired level below the upper frame 13 by means of a locking device 80 which is best shown in FIG. 5. The locking device 80 includes two flat disc-shaped plates 81 and 82 disposed over the bolt 68, the plate 81 being welded in a stationary position to the cross member 70 and the plate 82 being welded to the head 84 of the bolt 68 for rotation as the bolt is rotated. The plate 82 contains a series of openings 86 disposed in a circle around a peripheral portion thereof. The plate 81 contains a single opening 87 in a peripheral portion thereof which will register successively with each of the openings 86 as the bolt 68 and plate 82 are rotated through a complete circle. When the bolt 68 has been turned to place the mechanism 42 at the proper extension so as to place the roller 50 at the desired level, a cotter key 88 is inserted through any one of the openings 86 which is nearest in registry with the opening 87 and thence through the latter opening to lock the two plates 81 and 82 together in a fixed position of rotational alignment. In this manner, the roller 50 is locked at the desired level below the upper frame 13. A nut and bolt or other suitable fastener may be used in place of the cotter key 88 to lock the plates 81 and 82 together if preferred. A metal washer 89 is welded to the bolt 68 to confine a free rotating plastic washer 91 and a free rotating flat metal washer 93 against the cross member 70. 
     The mechanism 42 differs from other conventional forms of scissors extenders and jacks in that it includes a first and second pair of scissors 91a,b and a third and fourth pair of scissors 92a,b, wherein the first and second pair open toward the third and fourth pair and vice versa. All of the distal ends of which arms of the scissors 90a,b and 92a,b are pivotally connected to angles affixed to the corners of the plates 40 and 44 so that none of the scissors arms slide or translate along the plates as the mechanism 42 is extended or retracted. The mechanism 42 also includes a pair of relatively short alignment arms 94a,b pivotally connected to opposite end portions of the cross member 71 and to the pair of lower arms of the scissors 92a,b and another pair of short alignment arms 96a,b pivotally connected to opposite end portions of the cross member 70 and to the pair of upper arms of the scissors 90a,b. 
     Finding the precise point of attachment of the alignment arms 94a,b with the lower arms of the scissors 92a,b and of the alignment arms 96a,b with the upper arms of the scissors 90a,b, while critical for maintaining the plates 40 and 44 parallel with one another throughout the range of extension of the mechanism 42, will require some experimenting. One suitable example of the invention constructed by me employed upper and lower arms of the scissors 90a,b and 92a,b which were 391/2 inches in length between the centerline of the pivots at each end thereof. The alignment arms 94a,b and 96a,b were 261/2 inches in length between centerlines of the pivots at each end thereof. The arms 94a,b were pivotally connected to the lower arms of the scissors 92a,b a distance of 10 inches from the centerline of the lower end pivot of the latter. Similarly, the arms 96a,b, were pivotally connected to the upper arms of the scissors 91a,b a distance of 10 inches from the centerline of the upper end pivot of the latter. These dimensions allowed the plates 40 and 44 to maintain parallel alignment through a range of spacing of from 5 to 40 inches. 
     Referring now particularly to FIGS. 6-11, reinforcing rods 98 are shown interconnecting the pair of upper arms 100a,b of the scissors 90a,b, as interconnecting the lower arms 102a,b of the scissors 90a,b, as interconnecting the alignment arms 94a,b, as interconnecting the alignment arms 96a,b, as interconnecting the upper arms 104a,b of the scissors 92a,b and as interconnecting the lower arms 106a,b of the scissors 92a,b, respectively. 
     Although the present invention has been described with respect to specific details of a certain preferred embodiment thereof, it is not intended that such details limit the scope of this patent otherwise than as specifically set forth in the following claims.