US 3656419 A
A vibratory roller with an earth compacting drum having an axially balanced shaft which is journaled in the drum and power driven for rotation relative to the drum. The shaft carries a hollow chamber which is offset eccentrically from the axis thereof and which extends substantially the entire length of the shaft. Means are provided for admitting liquid to and discharging it from the chamber so that the amplitude of vibration of the shaft might be varied at any selected speed of rotation of the shaft.
Claims available in
Description (OCR text may contain errors)
I United States Patent [151 3,656,419 Boone  Apr. 18, 1972 s41 VIBRATORY ROLLER 2,963,914 12/1960 Dupouy ..74/87 3,011,355 12/1961 Carrier ..74/87  Invent 3,020,683 2/1962 Brandt ....74/87 x  Assignee: American Hoist & Derrick Company, Min- 3,048,089 8/1962 Kaltenegger ..94/50 neapolis, Minn. 3,078,730 2/1963 Clements ..74/87  Med: 1969 Primary Examiner-Jacob L. Nackenoff MN 811,811 AttrneyCarlsen, Carlsen, Sturm & Wicks 52 us. Cl ..94/50, 74/87 [571 ABSTRACT  Int. Cl. ..E0lc 19/28 A vibratory ll ith n earth compacting drum having an  Field of Search ..74/61, 87; 259/D1G. 42; 94/48, axially balanced h f which is jo'umaled in the drum and 94/50 power driven for rotation relative to the drum. The shaft car- I ries a hollow chamber which is offset eccentrically from the  References and axis thereof and which extends substantially the entire length UNITED STATES PATENTS v of the shafL Means are provided for admitting liquid to and discharging it from the chamber so that the amplitude of 2,248,478 7/1941 Mall vibration of the shaft might be varied at any selected speed of 2,67 l Kerr1dge..... rotation ofthe Shaft, 2,728,277 12/1955 McRae 94/50 UX 2,955,476 1960 Geil ..74/87 2 Claims, 4 Drawing Figures 60 3 E 44 29 2 22 22:12:: 24 T 38 5 9 2 y k 34 24 L/ 40 4/ 37 Z v l 2g fi m m if VIM, H W 4/0010 I 6 7 reams-Fee Pmmwmmz 3,656,419
7 SHEET 15F 2 v Z8 26 11" M iii! Hu l I W W W Tu IN VENIOR.
M51 l/M/ 4 3004/5 zhjzdzw fiwm VIBRATORY ROLLER Vibratory rollers are commonly used today for the compaction of soil, asphalt and other ground surface materials. The roller vibration is generally created by providing an eccentric weight or weights on a power driven rotary shaft extending axially through the roller drum. Varying dynamic forces are obtained by varying the speed of rotation of the shaft and weights. These forces are varied to change the amplitude of movement, or the vertical distance of movement, of the roller drum relative to the ground surface.
It is highly desirable that the operator be enabled to accurately control the amplitude of movement. This is due to the fact that optimum compaction results are achieved where the soil mass is vibrated at or near its resonant frequency. It is well known that when a vibrator is operated through a range of frequencies (vibrations per minute) with a constant dynamic force, there will be one frequency at which the soil will vibrate much more strongly than at any other frequency. However, with a constant dynamic force the amplitude and frequency of vibration are not separable. High frequency (rotation) produces high amplitude (vertical movement) and low frequency produces low amplitude. Thus the desired degree of amplitude control at any given frequency is not possible in presently known vibratory rollers.
In certain situations, such as compaction of a mat of asphalt road surface, it is desirable that roller vibration have a high frequency but at a low amplitude and in other situations it may be desirable to have a low frequency of vibration at a relatively high amplitude.
It is an object of this invention to provide a vibratory roller construction wherein the amplitude of vibration may be controlled independently of the frequency.
With such objective in mind the invention broadly comprises providing the roller drum shaft with an offset hollow chamber and a system for varying the amount of liquid in said chamber whereby the amplitude of drum vibration created by the shaft rotation can be varied atany given speed of rotation.
The above mentioned and other objects of the invention will be brought to light during the course of the following specification, reference being made to the accompanying drawings, in which FIG. 1 is a perspective side view of a self-propelled vibratory roller embodying the invention.
FIG. 2 is an enlarged vertical section through the roller drum taken on line 2-2 of FIG. 1 with certain components of the vibratory mechanism shown diagrammatically.
FIGS. 3 and 4 are similar partial cross sectional views through the lower portion of the drum to demonstrate the relationship between the amount of liquid in the eccentric chamber and the amplitude of movement of the drum.
Referring now more particularly to the drawings reference numerals will be used to denote like parts or structural features in the different views. A self-propelled vibratory compactor or roller is denoted generally by the numeral 10. It includes a roller unit 11 and a propulsion unit 12. The propulsion unit comprises a body 14 supported upon drive wheels 15 which are powered by an engine enclosed in housing 16. A steering wheel 17 for operating mechanism to relatively adjust units 11 and 12 about a connecting vertical pivot axis is controlled from the operator's station 18 as are various hydraulic controls 19 and 20.
The roller unit 11 comprises a frame 21 connected to unit 12 at the aforementioned pivot axis. The side bars of the frame support coaxial bearings 22 (FIG. 2) which jointly journal the end portions 24 of a cross shaft denoted generally at 25. A cylindrical roller or drum 26 has a pair of parallel circular end walls 27 which are interconnected by an annular ground engaging wall 28. Walls 27 have coaxial bearings 29 which are journaled respectively on portions 30 of shaft 25 which are located just within the end portions 24. It will accordingly be understood that shaft 25 is journaled for rotation in frame 21 and drum 26 is journaled for rotation on the shaft 25. The shaft 25 and drum 26 may accordingly rotate at different speeds on a common axis. The shaft in fact serves as an axle for the drum as the drum is moved over the ground surface.
Means are provided for power rotation of shaft 25 and for creating vibrations therein during said rotation. A fluid motor 34 is suitably mounted on frame 21 and has a driving connection with one end of shaft 25. Hydraulic fluid is circulated between a reservoir (not shown) on body 14 and the motor 34 through lines 35 and 36.
At its other end the shaft 25 is provided with an axial passageway 37. The end of this passageway is internally threaded for connection with a rotating coupling 38. Shaft 25 is provided with an elongated cylindrical chamber 39 extending substantially the entire length of the shaft. The chamber is offset to one side of the shaft axis so as to be in an eccentric position.
A tube 40 extends from the coupling 38 inwardly through passageway 37. A sea] 41 is provided at the end of tube 40 between the tube and the wall of passageway 37. Radial passageways 44 and 45 respectively connect passageway 37 with chamber 39 on opposite sides of seal 41.
A liquid transfer chamber 46 is mounted at some point on the body 14 and is connected by liquid line 47 with the coupling 38. Within the coupling 38 line 47 has open communication with passageway 37 but not the interior of tube 40. Accordingly, liquid may pass from chamber 46, through line 47, the coupling 38 and passageways 37 and 45 into chamber 39.
A supply tank 50 of air under pressure is also mounted on body 14. Line 51 connects tank 50 with chamber 46 and has a shut-off valve 52 therein. A line 54 extends from tank 50 to coupling 38 and connects through the coupling with the interior of tube 40. A controllable shut-off valve 55 is disposed in line 54. Accordingly, when valve 52 is open and valve 55 is closed air pressure will flow into chamber 46 forcing the liquid therein out through line 47 and into the chamber 39. On the other hand, when valve 52 is closed and valve 55 is open the air pressure will flow through line 54, tube 40 and passageway 44 forcing the liquid in chamber 39 back through passageways 45 and 37 and line 47 to chamber 46. Chamber 46 is provided with a valve 43 which is normally closed but which is opened to vent the chamber interior to the atmosphere when the system is operated to return liquid to the chamber. Similarly line 54 is provided with a bleed valve 53 which is normally closed but which is opened to allow air to escape from line 54 when the system is operated to move liquid from chamber 46 to chamber 39. Suitable means are provided for operating valves 52, 53, 54 and 55 from the operators station 18 such as by controls 19.
While the system has herein been described as operated by air, other gases under pressure may be used with equal effectiveness.
It will be noted that shaft 25 is somewhat enlarged as at 60 (FIG. 2) on the side which has chamber 39. This is to equalize the weight of the shaft around the shaft axis. Accordingly, when chamber 39 is empty the shaft is in balance and when rotated will not transmit any vibratory forces to the ground. When the roller is operated with chamber 39 empty only the static forces of the weight of the machine are transmitted to the ground. In this condition the rotation of shaft 25 by motor 34 would serve no useful purpose so it is left in fixed position serving solely as an axle or spindle for the drum 26.
To produce vibratory forces in the drum, valve 52 is opened causing liquid to flow into chamber 39. The weight of the liquid in the eccentrically located chamber 39 causes shaft 25 to become out of balance. Accordingly, when the shaft 25 is driven by motor 34 the shaft will vibrate by reason of centrifugal force of the added weight and these vibrations will be transmitted through bearings 29 to the drum and then to the ground G.
The greater amount of liquid admitted to the chamber 39, the greater will be the amplitude of vibration. This is demonstrated in FIGS. 3 and 4. When the chamber is filled to near capacity, as in FIG. 3, the distance of drum vibration as denoted by the facing arrows a-a is substantially greater than the distance denoted by arrows b-b in FIG. 4 where the chamber 39 has a minimal amount of liquid therein. Thus the amplitude of vibration can be significantly varied at any given speed of rotation of shaft 15.
Inasmuch as the speed of rotation of the shaft can be varied from zero to maximum and the amount of fluid in chamber 39 can be selectively varied, very fine control of dynamic forces can be obtained. This feature is not present in existing mechanisms where amplitude is created by rotational speed and accordingly is not separable therefrom.
The construction described accordingly economically and effectively carries out the aforementioned objectives. Having now therefore fully illustrated and described the invention, what I claim to be new and desire to protect by United States Letters Patent is:
1. In a vibratory roller for compacting soil or the like, and having a power driven rotary shaft mounted axially in a ground compacting drum, the improvement which comprises,
a. means forming a hollow chamber mounted on the shaft in a position eccentric with respect to the axis of rotation thereof, a reservoir of fluent material, c. first conduit means connecting the reservoir to the chamber, a source of air under pressure,
second conduit means connecting said source to the chamber, third conduit means connecting said source to said reservoir, and
g. valve means located in said second and third conduit means to selectively open or close the same.
2. In a vibratory roller,
a. a frame,
b. a drum journaled on the frame for rolling engagement with the ground surface,
c. a shaft extending axially through the drum,
(1. power means for rotating the shaft relative to the drum,
e. means on the shaft fonning a chamber disposed eccentrically with respect to the shaft axis,
f. a reservoir of liquid material supported by the frame,
g. a first conduit means connecting the reservoir to the chamber,
h. an air pressure source,
i. a second conduit means connecting said air pressure source to the chamber,
j. a third conduit means connecting the air pressure source to the reservoir, and
k. valve means located in said second and third conduit means to independently and selectively open said source to the chamber to move liquid from the chamber through the first conduit means from the chamber into the reservoir or to open said source to the reservoir to move liquid from the reservoir through the first conduit means from the reservoir into the chamber.