Claims
- 1. A vibratory road roller comprising a vibratory drum and a hydraulic vibrator device mounted coaxially with said drum, said vibrator device comprising a rotor mounted for rotation relative to said drum about the longitudinal axis of the drum, said rotor having a cavity open at a peripheral region of the rotor and adapted to contain a body of fluid which is eccentric of said axis, the rotor being surrounded by a swept annular surface fixed relative to said drum and so as to be contacted by and to contain said body of fluid in said cavity, and an out-of-balance mass to produce on rotation of the rotor a centrifugal force transmitted to said drum as a vibratory force by the pressure of said body of fluid on said swept annular surface.
- 2. A vibratory road roller according to claim 1, wherein said swept annular surface is an internal surface of a casing of the vibratory device, which casing surrounds the rotor and is fixed to said vibratory drum.
- 3. A vibratory road roller according to claim 1, wherein said vibratory device is one of two such devices, said two devices are respectively positioned adjacent the two ends of the drum and the rotors thereof are rotatable relatively to the drum in phase and in synchronism with each other, and the two devices are interconnected by a conduit operative to balance said fluid pressure in the two devices.
- 4. A vibratory road roller comprising a vibratory road-contacting drum and a hydraulic vibrator device mounted coaxially with said drum, said vibrator device comprising a rotor mounted for rotation relative to said drum about a longitudinal axis of the drum and coaxially surrounded by a swept annular surface fixed relative to said drum, an out-of-balance mass and drive means for rotating said rotor, said rotor having a cavity open at a peripheral region of the rotor and adapted to contain a body of fluid which is eccentric of said axis, contacts said swept annular surface and is contained thereby in said cavity, said out-of-balance mass producing on rotation of said rotor a centrifugal force transmitted to said drum as a vibratory force by the pressure of said body of fluid on said swept annular surface.
- 5. A vibratory road roller according to claim 4, wherein said vibratory device further comprises a casing within which said rotor is rotatably supported, said swept annular surface being an internal surface of said casing and said casing being fixed to said vibratory drum.
- 6. A vibratory road roller according to claim 5, further comprising bearings by which said rotor is rotatably supported in said casing of the device, and the rotor structure is mechanically balanced so that substantially no vibratory force is transmitted to the casing through said bearings.
- 7. A vibratory road roller according to claim 4, wherein said vibratory device is one of two such devices respectively positioned adjacent the two ends of said drum, each of the rotors of the two devices being coupled to said drive means so that the two rotors are rotatble, relative to the drum, in phase and in synchronism.
- 8. A vibratory road roller according to claim 7, wherein said two vibratory devices are interconnected by a conduit operative to balance said fluid pressure in the two devices.
- 9. A vibratory road roller according to claim 4, wherein the rotor of said vibratory device is adapted to operate as a centrifugal impeller to induce a flow of make-up fluid to replace leakage from said cavity at the rotor periphery, and a fluid reservoir is provided externally of said device from which the fluid to replace said leakage is supplied.
- 10. A vibratory road roller according to claim 9, wherein said external reservoir is provided by the internal volume of said drum, and a make-up pump is connected to supply the centrifugal impeller from the reservoir.
- 11. A vibratory road roller according to claim 4, wherein said out-of-balance mass comprises a piston mounted in said rotor so as to be free to move radially outwardly against said body of fluid, whereby on rotation of the rotor centrifugal force urging the piston radially outwardly is balanced by said fluid pressure.
- 12. A vibratory road roller according to claim 11, wherein said rotor has a radial bore providing said cavity, said piston is slidable in said radial bore which contains said body of fluid radially outwardly of the piston, and a pump is connected to supply fluid to the outer end of said bore to make up fluid leakage at the tip of the rotor and to maintain said fluid pressure whereby to retain the piston in a pressurebalanced radial position.
- 13. A vibratory road roller according to claim 12, wherein a fluid return port is positioned in a wall of said bore whereby said piston is automatically positioned to throttle the return port sufficiently to maintain said fluid pressure at a piston-balancing value.
- 14. A vibratory road roller according to claim 13, further comprising an adjustable pressure-control valve which senses said fluid pressure and operates to control the fluid supply to said bore by said pump whereby to maintain said piston at a predetermined pressure-balanced radial position.
- 15. A vibratory road roller according to claim 4, wherein said body of fluid provides at least a substantial part of said out-of-balance mass.
Priority Claims (2)
Number |
Date |
Country |
Kind |
31037/77 |
Jul 1977 |
GBX |
|
50836/77 |
Dec 1977 |
GBX |
|
Parent Case Info
This application is a division of Ser. No. 918,956, June 26, 1978, now U.S. Pat. No. 4,194,405 issued Mar. 25, 1980.
US Referenced Citations (8)
Divisions (1)
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Number |
Date |
Country |
Parent |
918956 |
Jun 1978 |
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