US 3901616 A
Description (OCR text may contain errors)
United States Patent 1191 Greening 14 1 Aug. 26, 1975 SELF-PROPELLED PAVER  Filed: July 22, 1974  Appl. No.: 490,318
 US. Cl. 404/102; 404/85; 404/118; 280/104.5 B  Int. Cl. EOIC 19/38  Field of Search 404/83, 85, l0l, 102, 118; 280/1045 B; 180/2402 OTHER PUBLICATIONS Barber-Greene Model SB50, Manual Page 6900, all pages (5).
Primary Examiner-Mervin Stein Assistant Examiner-Steven Hawkins [5 7] ABSTRACT An asphalt paver has a suspension which, in normal use, applies much of the paver weight to the screed, but includes a provision for forwardly tilting on bogie assemblies, to raise the screed and spreading auger for highway travel Main suspension frames are mounted beneath the hopper on trunnions and extend rearwardly to mount wheels aft of the center of gravity of the paver but forward of its lateral spreading auger. When jacks are operated downward to bear on the rear portions of the bogie suspension frames, they shift its weight distribution forward and lift the screed and spreading auger to permit highway travel.
6 Claims, 5 Drawing Figures SELF-PROPELLED PAVER BACKGROUND OF THE INVENTION Asphalt pavers commonly in use are of two principal types: towed and self-propelled. Towed pavers may have wheels or continuous tracks beneath the forward hopper of the paver, to support part of its weight; the remainder of the weight is conventionally supported on the screed plate which compacts the material discharged through a gate immediately forward of the screed.
Self-propelled pavers, on the other hand, usually have sets of four wheels or two track bogies tobear the paver weight. The screed plate is carried on rearward extending pivoted lever arms, which may be pressed downward by hydraulic jacks to urge the screed plate against the surface being paved. Using this conventional arrangement, no substantial part of the weight of the paver can be applied to the screed; to do this the downward force on the screed would have to raise the rear wheels relative to the surface. Another problem with conventional self-propelled pavers is that, using large rear wheels for propulsion, narrows the central space exists between the wheels, through which the asphaltic material in the hopper must be conveyed, then to be transported laterally outward for spreading. This problem has required the use of conveyor belts within the pavers, as well as other complex material delivery and spreading mechanisms.
SUMMARY OF THE INVENTION The objects of the present invention include utilizing the simple and effective features of towed pavers in one adapted for self-propulsion. Specifically the objects include providing a suspension which applies a substantial portion of the weight to the screed during paving, but which for highway travel raises the screed and associated spreading components well above a highway surface. Other objects will be apparent from the disclosure which follows.
Summarizing generally, and without limiting the scope hereof, I provide a self-propelled paver whose suspended components include a hopper are generally similar to those of conventional towed pavers. These include a hopper whose aft-sloping bottom wall extends beneath a lateral gate which, when open, permits paving material to pass to a lateral spreading auger and then to the compactor screed.
A trunnion-mounted suspension is used to bear the load of the forward portion of the paver when used for paving; the screed at the rear then bears the aft weight of the paver. However, for highway travel the load is redistributed among the members of the suspension to raise the screed and auger to a safe height above the pavement. This is achieved as follows:
Each suspension assembly has a longitudinally extending suspension frame with a forward portion at which is located a bogie axis and a rear portion having a rear wheel axis aft of the center of gravity of the paver. At the forward bogie axis is mounted a pivoting carriage, whose wheels are driven by hydraulic motors. At the rear axis a rear wheel is housed beneath the inward slope of the hopper wall, with a chain drive extending to it from the hydraulic motors at the forward wheels.
In paving use, the rear wheel bears only that part of the weight which is distributed to it by balancing the suspension frame at the trunnion axis. For highway travel, however, elevating jacks operate downward from the paver onto the rear portions of the suspension frames, so that they no longer balance about the trunnion axis. The jacks raise and tilt the paver on its trunnion axis, to raise the screed and the spreading auger from the surface sufficiently to permit highway travel.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a self-propelled paver embodying the present invention, shown partly schematically and partly fragmentarily.
FIG. 2 is a side view seen from the left of FIG. 1.
FIG. 3 is an enlarged perspective view of the bogie assembly at the left side of FIG. 1, as seen partly from above and the right.
FIG. 4 is an enlarged fragmentary sectional view seen along line 44 of FIG. 1.
FIG. 5 is a sketch corresponding to FIG. 2, the phantom lines showing tilting accompanying the operations of the hydraulic jacks.
DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment of the present invention is an adaptation of that type of paver heretofore towed by a dump truck. Thus the paver generally designated 10 has a forwardly located full width hopper 11 whose bottom surface 12 slopes downward and aft. Paver side walls 13 have, along their forward upper edges, angularly adjustable lead-in wing portions 14, to receive material dumped into the hopper l l as from a dump truck. A forward lip 15 of the hopper l l is conventionally reinforced. Even though the paver 10 is normally selfpropelled, it may optionally be equipped with a pair of conventional towing arms 16, one of which is shown in phantom in FIG. 1, whose rotatable inwardly presented discs 17 fit within the rims of rear wheels of a towing vehicle.
As is conventional, the aft sloping bottom 12 of the hopper 11 continues beyond a gate 18 having a horizontal hinge 19 along the lower margin of a vertical wall 20 and opened and closed by a conventional linkage 21. The portion of the bottom 12 aft of the gate 18 is designated as the rearward hopper bottom surface 22. This terminates in a downward extending forward auger compartment wall 23; spacedly aft of it is a rear auger compartment wall 24, both of which extend laterally across the full width of the paver 10. Between them, mounted in aligned bearings on a plurality of auger struts 26 is the lateral shaft 27 of a conventional spreading auger 28, whose flights proceed from center in opposite senses so as to spread paving material outwardly.
A conventional screed plate assembly generally designated 29 is mounted by conventional means. For adjusting its height and crown such conventional means include left and right screed plate adjusting struts 30. The screed plate assembly functions to compact paving material discharged under the gate 18 and spread by the auger.
In a conventional towed paver, a substantial part of the weight of the machine, including the weight of the material filled into the hopper 11, is borne by the screed plate pressing upon discharged paving material, the remainder being borne by forward wheels or track supports, positioned beneath the forward part of the screed plate assembly 29 to bear downward under the.
weight of the paver and material, as with a towed paver. However, for highway travel the suspension assemblies 33 are so actuated as to tilt'the paver and raise the screed plate assembly 29 from the pavement. The preferred suspension assembly 33 is a bogie-type assembly. The suspension assembly 33 at the left of FIG. 1 is illustrated in FIG. 3; a corresponding assembly at the other side is a mirror image thereof.
A longitudinally extending principal frame member generally designated 34 is a welded assembly made of steel plate members arranged vertically. When viewed in plan form it consists of two generally U-shaped portions: a broader forward U'shaped portion 35 between which the forward drive wheels are mounted, and a narrower rear frame portion 36 between which a rear drive wheel is mounted. As best seen from FIG. 3, the outer'side of the rear frame portion 36 is a continuation of the outer side of the forward portion 35; whereas the inner side of the narrower rear frame portion 36 extends aft from approximately the midpoint of the lateral member 37 of the forward U-shaped portion 35. Immediately forward of the lateral member 37 is welded a tubular principal trunnion mount 38; from it outer and inner side frame portions 39, 40 extend forwardly. As seen in FIG. 3 the inner side 40 has an upwardly rounded reinforced part 41 whose strength compensates for the partial slots 42 which extend upwardly from itslower edge and arcuately about a forward bogie axis 44 at the forward ends of the side frame portions 39, 40.
The rear U-shaped frame portion 36 comprises similar inner and outer side plates 46 whose rear upwardslanting portions 47 are bridged by a rigidconnector plate 48, on which is welded an attachment fitting 49 for the vertical actuating strut hereafter described. A rear wheel axle 51 is mounted between the rear portion of the side plates 46 by bearings 52 in adjustable plates 53 which position the rear axle 51 slightly aft of the center 'of gravity of the suspended paver portions as illustrated in FIG. 5.
The tubular trunnion mounts 38 of the left and right suspension assemblies 33 are at a common lateral axis of the paver 10. This common axis is well forward of the center of gravity of the suspended portions of the paver 10. In normal operation, when no pressureis exerted on the attachment fitting 49, each suspension assembly 33 as a whole may pivot on the common lateral axis of the trunnions 38, dividing the suspended weight between the rear axle 51 and the forward bogie axis 44.
On the forward axis 44 is a shaft 55, seen in FIG. 3, on which is pivotally mounted a forward drive carriage assembly generally designated 56. The carriage assembly 56 comprises a pair of parallel vertical fore-and-aft extending carriage plates 57 whose midpoints are mounted on the shaft 55 from which the carriage plates 57 extend both forwardly and aft. The carriage plates 59 spaced closely forward and aft of the pivot shaft 55. As seen in FIGS. 1 and 3, the inner carriage plate 57 is located closely inward of the inner side 40 of the forward U-shaped portion 35 of the frame 34; while the correspondingly numbered outer carriage plate 57 is spaced well inwardly from the outer side portion 39 of the suspension frame 34. In the longitudinal space so provided, a chain drive is accommodated.
Drive sprockets 61 on the axles 58, 59 mount a forward chain 62 which operatively connects them, preferably also passing over a chain tightening idler 63 supported in a raised position outwardly of the outer plate 57. An outer sprocket 64 mounted on the second drivmount a front driving axle 58 and a second driving axle ing axle 59 outwardly of the sprocket 61 carries a-rear chain 65 which extends rearward above and below the lateral frame member 37 to and over a driven sprocket 66 keyed to the rear wheel axle 51.
Secured on this a'xle 51 is a rubber tired rear wheel 68. Secured on the front axle and second axle 58, 59
are pairs of similar forward wheels 69. Wheels are preferred, in the present embodiment, to track propulsion; but obviously track-laying sprockets or bogiesmight be used. Accordingly, the wheels are sometimes herein referred to as rotatable support means or drive members.
Mounted on the inner vertical plate 57 at the front driving axle 58 is a conventional hydraulic drive motor 71. A similar motor 71 is mounted in alignment with and connected to the second driving axle'59 on a small mounting plate 72 beyond the inner side member 40 of the forward U-shaped frame 35, being there supported by pairs of studs 73 which extend from the inner carriage plate 57 through the arcuate slots 42. As will be apparent, the forward chain 62 causes the motors 71 to exert equal torques on the front axle 58 and second axle 59, while the rear chain 65 transfers power to the rearwheel axle 51.
The left and right powered suspension assemblies 33 so described are mounted immediately inward of the side walls 13 of the paver hopper 11, as best seen in FIGS. 1 and 4. Referring to FIG. 1, in a downward extending portion of the hopper side wall -13 is an outer trunnion bushing 75. A similar inner trunnion bushing 76 is supported by a structural rib 77 beneath the hopper bottom 12 and extending forwardly from the forward auger compartment wall 23, in lateral alignment with the outer bushing at a spacing sufficient to accommodate of the suspension assembly 33. A trunnion axle 78 extends through the bushings 75, 76 and through the tubular trunnion mount 38 of the suspension assembly 33. When, as in paving use, no load is applied to the strut attachment fitting 49,.the suspension frame 34 pivots freely, dividing the applied load between the rear axle 51 and the bogie axis 44 on which the forward drive carriage assembly 56 is tiltably mounted. v
One 'of the disadvantages of conventional selfpropelled pavers is the space requirement of their large main wheels, forward of a liftable screed but aft of the center of gravity. Such main wheels require broad housings, narrowing the width of the hopper gate between them. The paving material must be delivered through such relatively narrow gate and then spread relatively far sideward. To deliver the necessary quantity of material through a narrow gate sometimes requires a conveyor belt.
The present invention minimizes this problem, because the suspension described takes little space away from the hopper 11. From the side walls 13, the hopper 11 has narrow inward and downward sloping portions 80 which, near the front of the paver directly intersect the hopper bottom 12, as shown at the right side of FIG. 1. The slanting line of intersection extends aft and reaches a point far enough inward to accommodate beneath it the narrow rear suspension frame portion 36. Aft of this point the sloping portions 80 are joined by downward-extending vertical inner hopper side wall portions 81, as seen inFIG. 4. These hopper side wall portions 81 are thus offset inwardly of the side walls 13 sufficiently to provide a somewhat tunnel-likehousing for the U-shaped rear frame portion 36 of the suspension assemblies 33. Thus the present suspension takes away only slightly from the hopper space otherwise availab e, maximizes the width of the'hinged gate 18, and minimizes the distance over which the spreading auger 28 must operate to equalize the delivery of paving material. By maximizing the width of the gate 18, a satisfactory volume of aft flow over the bottom surface 12 is obtained without need for a longitudinal conveyor belt.
Continuing aft of the gate 18, generally aligned with the vertical inner hopper wall portions 81, are vertical inner body walls 82 spaced inward of the outer walls 13. Between the body walls 82 are accommodated the power components to be described.
A conventional gasoline engine generally designated 84 powers a conventional hydraulic power source 85 and its controls, not shown. Through them power may be supplied selectively to the hydraulic motors 71 of the left and right powered suspension assemblies 33, to drive and steer the paver. Power from the engine 84 to rotate the lateral spreading auger 28 may be supplied by a mechanical or hydraulic drive 86, shown schematically. Hence, paving material which slides by gravity down the sloping bottom surface 12 of the hopper l1, beneath the opened gate 18 to and over the forward auger compartment wall 23, will be spread by the auger 28 evenly outward over the paver width.
For convenient operation, an operators control panel 88 is mounted on a platform 89 which covers the hydraulic power source 85 and has a rearward platform extension 90 on which an operators chair 91 may be conveniently mounted.
In addition to supplying power to the motors 71 and other components, the hydraulic power source 85 is also connected through conventional controls to a pair of large, vertical hydraulic linear actuators or jacks 93. These are mounted with their lower ends pivotally connected to the attachment fittings 49 at the rear of the suspension frames 33, and with their upper ends held by fitting brackets 94 mounted inwardly of the paver side walls 13. When no pressure is applied to the jacks 93 they have no effect on the weight distribution. However, when it is desired to relieve the weight on the screed plate assembly 29 and lift it from the surface, as shown in phantom lines in FIG. 5, the hydraulic actuators 93 bring about an entirely different distribution of the suspended weight; in effect they change the suspension frames 34 from pivoting frames to fixed position frames. Thus, as best seen in FIG. 5, extension of the actuators 93 to the phantom line position elevates the body of the paver l0, tilting it upward about the trunnion axle 78 and thus raising the screed plate assembly 29 and spreading auger 28 sufficiently for highway travel. Although the suspension frames 34 are in effect fixed in position for highway travel, a degree of flexibility is still provided by the pivoting of the forward drive carriage assembly 56 on the forward bogie axis 44.
The present invention is particularly advantageous in providing superior traction when normally operated as a paver, with great viability for movement on job sites, etc. In addition to affording adequate provision for short-distance highway travel, the simple jackaugmented suspension is also advantageously used in maneuvering the paver on difficult terrain, in accommodating the height of the screed plate assembly 29 and auger 28 to temporarily encountered conditions.
The present invention may be modified for other uses. A conventional vibrator to vibrate the hopper bottom may be used to aid the flow of paving material. Without use of the hydraulic power system described, and coupling the auger 28 rotatively to forward movementof the paver 10, the invention is advantageously applied to a paver towed by a pair of conventional tow ing arms 16, which may be towed along a highway, without hoisting, by actuating the hydraulic jacks 93 to raise the screed assembly 29 and auger 28. Likewise the suspension of the present invention may be useful for construction vehicles other than pavers, in which a component at one side of the center of gravity normally bears on the surface but is to be raised under special circumstances.
From this disclosure, other modifications in structure, mechanism and manner of use will suggest themselves to persons having ordinary skill in the art.
1. A self-propelled paver for asphaltic materials and the like, of the type having suspended components including hopper, lateral material spreading means, and a rear compactor screed on which part of the weight is borne during paving, characterized in having a powered suspension adapted alternatively for paving use, in which the compactor screed bears a substantial portion of the weight, and for highway travel in which it is raised from the pavement, said suspension comprising levered assemblies at the left and right sides of the paver and mounted pivotally thereto along a common lateral axis forward of the center of gravity, each said levered assembly comprising a plurality of rotatable drive members and including a longitudinally-extending suspension frame having trunnion means to mount to such common lateral axis, and having an axis forward thereof and a rearward axis aft of the center of gravity of the paver,
a forward drive member assembly pivotally mounted at said forward axis and a rear drive member mounted at said rear axis,
motor means and a power source therefor,
chain and sprocket drive means driven thereby connecting said drive members for rotation at the same driving speed, and
powered actuator means, operating between the suspension frame and the suspended portions of the paver, to tilt the suspended portions on the trunnion means and raise the rear portions thereof relative to the rear portion of the bogie suspension frame,
whereby to permit highway travel.
2. A self-propelled paver as defined in claim 1, wherein said forward drive member assembly includes a carriage frame rockably mounted on said forward axis of the suspension frame and including, respectively forwardly and aft of said forward suspension frame axis, a front axle and a second axle on which rotatable drive members are mounted.
3. A self-propelled paver as defined in claim 1, in
which the motor means are secured to and directly drive the drive members of said forward assembly,
the sides of said hopper paver have rear portions sloping inward to an offset and beneath which are accommodated the rear portions of the suspension frames, the rear drive members, and means to drive same.
4. A self-propelled paver as defined in claim 1, in
which said motor means are hydraulic, and
said powered actuator means and hydraulic jacks actin g downwardly onto rear portions of the bogie suspension frames.
5. A paver for asphaltic materials and the like, comprising suspended components including a hopper having a bottom sloping downward and aft, and having side walls including inward offset junctures with the bottom wall, and having a gate between said inward offset junctures,
a material discharge section aft thereof including a spreading auger extending laterally outward of said junctures and means to rotate same when the paver is moved forward,
a compactor screed rearwardly thereof on which part of the paver weight is borne during paving, together with a suspension adapted alternatively for paving use, in which the compactor screed bears a substantial portion of said weight, and for highway travel in which it is raised from the pavement, said suspension comprising levered assemblies at the left and right sides of the paver and mounted pivotally thereto along a common lateral axis forward of the center of gravity, each said levered assembly comprising a plurality of rotatable drive members and including a longitudinally-extending suspension frame having trunnion means to mount to such common lateral axis, and having a forward portion including an axis forward of said common axis and a rear portion including a rearward axis aft of the center of gravity of the paver,
forward rotatable support means mounted at said for ward axis,
rear rotatable support means mounted at said rearward axis forwardly of the spreading auger and between the paver sides and said inward offset junctures, and
elevating jack means, operating downwardly from the suspended components of the paver onto rear portions of the bogie suspension frames, to tilt the suspended components forwardly on the trunnion means,
whereby to raise the screed and spreading auger for highway travel.
6. For use with a vehicle normally supported on one side of its center of gravity by a surface-bearing component,
a suspension adapted normally to provide support at the opposite side of the center of gravity, and alternately to raise said surface-bearing component and support the entire vehicle, comprising a levered suspension frame having trunnion means pivotally mounted on a lateral axis on such opposite side of the center of gravity, and having forwardly thereof a forward rotatable support memher,
the suspension frame extending to a point aft of the center of gravity and there having a rear rotatable support member,
whereby in normal operation that portion of the suspended weight of the vehicle reacted at said trunnion means will be pivotally divided between the rotatable support members forward and aft of said trunnion means, together with powered actuator means, operating between said suspension frame and the suspended portions of the vehicle, to raise said surface-bearing component from the surface and, in combination with the trunnion means, to fix the angular position of the suspension frame relative to the trunnion means,
whereby to cause the suspension frame to bear the entire suspended weight of the vehicle.