Patent GB-569977-A (GB)
Title: Improvements relating to road-building machines
IPC: E01C19/48
Filed: 1943-07-07
Abstract: 569,977. Road-building machines. AVELING- BARFORD, Ltd., and CUPPLEDITCH, C. D. July 7, 1943, No. 11026. [Class 107] [Also in Group XXIV] Relates to road-building machines for laying asphaltic or other plastic or semi-plastic surfacing material wherein a container for the material, spreading means and finishing means are mounted on a carriage partly supported slidably on the ground, and comprises the provision of a single rigid frame carrying said receptacle and spreading and finishing means, the frame being supported by a number of pairs of abutment elements so disposed and articulated thereto that the vertical displacement of any one of the abutment elements due to irregularity of the ground is reproduced to a fractional extent only at the position of the machine from which the levelling of the surface is controlled. As shown, the main frame 1 has rigidly fixed thereto a drawbar comprising beams 9 pivoted at 10a to an arbor 17 rotatably held in a slide block 15 by a pin 14 which also forms a pivot for a fore carriage comprising beams 12 and tandem wheels 13; the slide block 15 may be received in guides in a trolley unit as in Specification 562,973. At the rear of the frame 1 are laterally adjustable channel iron frames 20 with side limbs 19 fitting together telescopically and held after adjustment by pins engaging brackets 22; at each end of each frame 20 are guides 23 for beams 24 pivoted at 25 to the frames 20 and having at each end pivots 27 for slipper shoes 26 carrying guides 31 embracing the beams. During transport of the machine, the beams 24 may be locked to the forward guides 23 by pins. Within the beams 24 are tandem wheels 38 each pair of which is carried by a beam pivoted in a slide block adjustable through a spring by a lever 36 and screw 34, whereby the wheels may be adjusted to support the machine for transport or to engage the road to prevent side-slip of the machine. A levelling screed 40 is carried centrally of the frame 1 immediately behind a hopper 41 for the material, the screed and hopper being laterally extensible; the hopper has ends 42 terminating in shoes which slide on the ground and held so as to be freely movable vertically by slots 43 and bolts 44. The material is spread over the width of the screed by oppositely driven screws 45. For asphalt, &c. the screed 40 may comprise a roller, Figs. 10 and 10a, mounted below a box 1 beam 46 provided with tubes 47 for the passage of hot air, &c. and adjustable vertically by trunnion nuts 49 and screws 50 separately driven by chains through hand-wheels 56, Fig. 2a; the roller may be in two parts each divided into sections keyed to arbors 60, 62, with spigot and socket connections, and driven from a shaft 69 through a chain 66 tensioned by a jockey sprocket 76, the roller preferably having a peripheral speed slightly greater than that of travel of the machine and in the same direction. Vertical channel members, with wearing pads, guide the beam 46, and an angle plate bolted to the main frame seals the gap above the beam to prevent escape of material. The roller screed may be replaced by an oscillating screed comprising a boxbeam 80, Figs 12 and 13, adjusted by the same means as used for the beam 46, a pivoted radius rod 81 counteracting lateral thrust on the beam; the screed proper comprises a hollow rectangular bar 80 adjustably oscillated through links 103. 101, 93, 97, and having bolted to its lower face a blade 87 divided into short lengths and having its forward edge inclined upwardly and rearwardly while on its lower face are V-shaped teeth cut at an incline; the lower face itself may be inclined forwardly and upwardly except at the rear. The beam 80 has a front closure plate 90, Fig. 13, held by pegs engaging apertures and by tension springs, the plate 90 having rubbing contact with a facing 91 on the bar 86. The parts may be driven from the trolley of Specification 562,973, [Group XXXI], through clutches 109, Fig. 5, mounted on the shafts of the rear friction rollers of the trolley, the clutches being normally held free by springs 110 and engaged, through cables 113 in flexible tubes 113a, by a crank shaft 117 rocked by a link 120, crank shaft 122 and pedal 125, the pedal carrying a pivoted detent 127, Fig. 6, pressed by a spring 130 and provided with teeth adapted to engage a rack 126 to hold the clutches in engagement. The drive is effected through a chain, bevel gearing 136, 137, Figs. 1 and 2, cardan shaft 140, and gears 143-145; the gear 144 drives the spreader screws 45 independently through bevel gearing, epicyclic gearings 151 controlled by levers 153 through band brakes and chain gearing, while the gear 145 drives a shaft 157 which passes through a tube 147a traversing the hopper 41 and adapted, through a clutch 168, Fig. 26, to drive either a pinion 166 or worm reduction gearing 74. The latter is adapted to drive the rotary screed, while the pinion 166 meshes with a gear 179, Figs. 24 and 26, which, through change-speed gearing 176, 177, 181, 182, drives a crank shaft 174 which oscillates the reciprocating screed through connecting rod 173. The worm gearing 74 may also be driven by a removable crank handle 193. The machine may be wholly mounted on wheels or on skids or partly on endless tracks, and may be self-propelled or hauled by a tractor, the parts then being driven by a prime mover on the machine.